release: 4.2.0

Co-authored-by: Volodymyr Patuta <6977238-fiplox@users.noreply.gitlab.com>

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.editorconfig

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+root = true
+
+[*.rs]
+end_of_line = lf
+insert_final_newfile = true
+indent_style = space
+indent_size = 4

.gitignore

@@ -2,3 +2,8 @@
 target/
 **/*.rs.bk
 .DS_Store
+*.pdb
+exercises/clippy/Cargo.toml
+exercises/clippy/Cargo.lock
+.idea
+.vscode

.gitpod.yml

@@ -0,0 +1,7 @@
+tasks:
+  - init: /workspace/rustlings/install.sh
+    command: /workspace/.cargo/bin/rustlings watch
+
+vscode:
+  extensions:
+    - rust-lang.rust@0.7.8:CvNqMTgDdt3UXt+6BCDTVg==

.replit

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+language = "rust"
+run = "[ -x ~/.cargo/bin/rustlings ] && ~/.cargo/bin/rustlings watch || ./install.sh"

.travis.yml

@@ -1,11 +0,0 @@
-language: rust
-rust:
-  - stable
-  - beta
-  - nightly
-script: cargo test --verbose
-matrix:
-  allow_failures:
-    - rust: nightly
-  fast_finish: true
-cache: cargo

CHANGELOG.md

@@ -1,3 +1,192 @@
+<a name="4.2.0"></a>
+## 4.2.0 (2020-11-07)
+
+#### Features
+
+*   Add HashMap exercises ([633c00cf](https://github.com/rust-lang/rustlings/commit/633c00cf8071e1e82959a3010452a32f34f29fc9))
+*   Add Vec exercises ([0c12fa31](https://github.com/rust-lang/rustlings/commit/0c12fa31c57c03c6287458a0a8aca7afd057baf6))
+* **primitive_types6:**  Add a test (#548) ([2b1fb2b7](https://github.com/rust-lang/rustlings/commit/2b1fb2b739bf9ad8d6b7b12af25fee173011bfc4))
+* **try_from_into:**  Add tests (#571) ([95ccd926](https://github.com/rust-lang/rustlings/commit/95ccd92616ae79ba287cce221101e0bbe4f68cdc))
+
+#### Bug Fixes
+
+*   log error output when inotify limit is exceeded ([d61b4e5a](https://github.com/rust-lang/rustlings/commit/d61b4e5a13b44d72d004082f523fa1b6b24c1aca))
+*   more unique temp_file ([5643ef05](https://github.com/rust-lang/rustlings/commit/5643ef05bc81e4a840e9456f4406a769abbe1392))
+* **installation:**  Update the MinRustVersion ([21bfb2d4](https://github.com/rust-lang/rustlings/commit/21bfb2d4777429c87d8d3b5fbf0ce66006dcd034))
+* **iterators2:**  Update description (#578) ([197d3a3d](https://github.com/rust-lang/rustlings/commit/197d3a3d8961b2465579218a6749b2b2cefa8ddd))
+* **primitive_types6:**
+  *  remove 'unused doc comment' warning ([472d8592](https://github.com/rust-lang/rustlings/commit/472d8592d65c8275332a20dfc269e7ac0d41bc88))
+  *  missing comma in test ([4fb230da](https://github.com/rust-lang/rustlings/commit/4fb230daf1251444fcf29e085cee222a91f8a37e))
+* **quiz3:**  Second test is for odd numbers, not even. (#553) ([18e0bfef](https://github.com/rust-lang/rustlings/commit/18e0bfef1de53071e353ba1ec5837002ff7290e6))
+
+<a name="4.1.0"></a>
+## 4.1.0 (2020-10-05)
+
+#### Bug Fixes
+
+*   Update rustlings version in Cargo.lock ([1cc40bc9](https://github.com/rust-lang/rustlings/commit/1cc40bc9ce95c23d56f6d91fa1c4deb646231fef))
+* **arc1:**  index mod should equal thread count ([b4062ef6](https://github.com/rust-lang/rustlings/commit/b4062ef6993e80dac107c4093ea85166ad3ee0fa))
+* **enums3:**  Update Message::ChangeColor to take a tuple. (#457) ([4b6540c7](https://github.com/rust-lang/rustlings/commit/4b6540c71adabad647de8a09e57295e7c7c7d794))
+* **exercises:**  adding question mark to quiz2 ([101072ab](https://github.com/rust-lang/rustlings/commit/101072ab9f8c80b40b8b88cb06cbe38aca2481c5))
+* **generics3:**  clarify grade change ([47f7672c](https://github.com/rust-lang/rustlings/commit/47f7672c0307732056e7426e81d351f0dd7e22e5))
+* **structs3:**  Small adjustment of variable name ([114b54cb](https://github.com/rust-lang/rustlings/commit/114b54cbdb977234b39e5f180d937c14c78bb8b2))
+* **using_as:**  Add test so that proper type is returned. (#512) ([3286c5ec](https://github.com/rust-lang/rustlings/commit/3286c5ec19ea5fb7ded81d047da5f8594108a490))
+
+#### Features
+
+*   Added iterators1.rs exercise ([9642f5a3](https://github.com/rust-lang/rustlings/commit/9642f5a3f686270a4f8f6ba969919ddbbc4f7fdd))
+*   Add ability to run rustlings on repl.it (#471) ([8f7b5bd0](https://github.com/rust-lang/rustlings/commit/8f7b5bd00eb83542b959830ef55192d2d76db90a))
+*   Add gitpod support (#473) ([4821a8be](https://github.com/rust-lang/rustlings/commit/4821a8be94af4f669042a06ab917934cfacd032f))
+*   Remind the user of the hint option (#425) ([816b1f5e](https://github.com/rust-lang/rustlings/commit/816b1f5e85d6cc6e72673813a85d0ada2a8f84af))
+*   Remind the user of the hint option (#425) ([9f61db5d](https://github.com/rust-lang/rustlings/commit/9f61db5dbe38538cf06571fcdd5f806e7901e83a))
+* **cli:**  Added 'cls' command to 'watch' mode (#474) ([4f2468e1](https://github.com/rust-lang/rustlings/commit/4f2468e14f574a93a2e9b688367b5752ed96ae7b))
+* **try_from_into:**  Add insufficient length test (#469) ([523d18b8](https://github.com/rust-lang/rustlings/commit/523d18b873a319f7c09262f44bd40e2fab1830e5))
+
+<a name="4.0.0"></a>
+## 4.0.0 (2020-07-08)
+
+#### Breaking Changes
+
+*   Add a --nocapture option to display test harnesses' outputs ([8ad5f9bf](https://github.com/rust-lang/rustlings/commit/8ad5f9bf531a4848b1104b7b389a20171624c82f))
+*   Rename test to quiz, fixes #244 ([010a0456](https://github.com/rust-lang/rustlings/commit/010a04569282149cea7f7a76fc4d7f4c9f0f08dd))
+
+#### Features
+
+*   Add traits README ([173bb141](https://github.com/rust-lang/rustlings/commit/173bb14140c5530cbdb59e53ace3991a99d804af))
+*   Add box1.rs exercise ([7479a473](https://github.com/rust-lang/rustlings/commit/7479a4737bdcac347322ad0883ca528c8675e720))
+*   Rewrite try_from_into (#393) ([763aa6e3](https://github.com/rust-lang/rustlings/commit/763aa6e378a586caae2d8d63755a85eeba227933))
+*   Add if2 exercise ([1da84b5f](https://github.com/rust-lang/rustlings/commit/1da84b5f7c489f65bd683c244f13c7d1ee812df0))
+*   Added exercise structs3.rs ([b66e2e09](https://github.com/rust-lang/rustlings/commit/b66e2e09622243e086a0f1258dd27e1a2d61c891))
+*   Add exercise variables6 covering const (#352) ([5999acd2](https://github.com/rust-lang/rustlings/commit/5999acd24a4f203292be36e0fd18d385887ec481))
+
+#### Bug Fixes
+
+*   Change then to than ([ddd98ad7](https://github.com/rust-lang/rustlings/commit/ddd98ad75d3668fbb10eff74374148aa5ed2344d))
+*   rename quiz1 to tests1 in info (#420) ([0dd1c6ca](https://github.com/rust-lang/rustlings/commit/0dd1c6ca6b389789e0972aa955fe17aa15c95f29))
+*   fix quiz naming inconsistency (#421) ([5563adbb](https://github.com/rust-lang/rustlings/commit/5563adbb890587fc48fbbc9c4028642687f1e85b))
+*   confine the user further in variable exercises ([06ef4cc6](https://github.com/rust-lang/rustlings/commit/06ef4cc654e75d22a526812919ee49b8956280bf))
+*   update iterator and macro text for typos and clarity ([95900828](https://github.com/rust-lang/rustlings/commit/959008284834bece0196a01e17ac69a7e3590116))
+*   update generics2       closes #362 ([964c974a](https://github.com/rust-lang/rustlings/commit/964c974a0274199d755073b917c2bc5da0c9b4f1))
+*   confusing comment in conversions/try_from_into.rs ([c9e4f2cf](https://github.com/rust-lang/rustlings/commit/c9e4f2cfb4c48d0b7451263cfb43b9426438122d))
+* **arc1:**  Passively introduce attributes (#429) ([113cdae2](https://github.com/rust-lang/rustlings/commit/113cdae2d4e4c55905e8056ad326ede7fd7de356))
+* **box1:**  fix comment typo (#426) ([bb2ca251](https://github.com/rust-lang/rustlings/commit/bb2ca251106b27a7272d9a30872904dd1376654c))
+* **errorsn:**  Try harder to confine the user. (#388) ([2b20c8a0](https://github.com/rust-lang/rustlings/commit/2b20c8a0f5774d07c58d110d75879f33fc6273b5))
+* **from_into.rs:**  typo ([a901499e](https://github.com/rust-lang/rustlings/commit/a901499ededd3ce1995164700514fe4e9a0373ea))
+* **generics2:**  Guide students to the answer (#430) ([e6bd8021](https://github.com/rust-lang/rustlings/commit/e6bd8021d9a7dd06feebc30c9d5f953901d7b419))
+* **installation:**
+  *  Provide a backup git reference when tag can't be curl ([9e4fb100](https://github.com/rust-lang/rustlings/commit/9e4fb1009f1c9e3433915c03e22c2af422e5c5fe))
+  *  Check if python is available while checking for git,rustc and cargo ([9cfb617d](https://github.com/rust-lang/rustlings/commit/9cfb617d5b0451b4b51644a1298965390cda9884))
+* **option1:**
+  *  Don't add only zeros to the numbers array ([cce6a442](https://github.com/rust-lang/rustlings/commit/cce6a4427718724a9096800754cd3abeca6a1580))
+  *  Add cast to usize, as it is confusing in the context of an exercise about Option ([f6cffc7e](https://github.com/rust-lang/rustlings/commit/f6cffc7e487b42f15a6f958e49704c93a8d4465b))
+* **option2:**  Add TODO to comments (#400) ([10967bce](https://github.com/rust-lang/rustlings/commit/10967bce57682812dc0891a9f9757da1a9d87404))
+* **options1:**  Add hint about Array Initialization (#389) ([9f75554f](https://github.com/rust-lang/rustlings/commit/9f75554f2a30295996f03f0160b98c0458305502))
+* **test2:**  name of type String and &str (#394) ([d6c0a688](https://github.com/rust-lang/rustlings/commit/d6c0a688e6a96f93ad60d540d4b326f342fc0d45))
+* **variables6:**  minor typo (#419) ([524e17df](https://github.com/rust-lang/rustlings/commit/524e17df10db95f7b90a0f75cc8997182a8a4094))
+
+<a name="3.0.0"></a>
+## 3.0.0 (2020-04-11)
+
+#### Breaking Changes
+
+* make "compile" exercises print output (#278) ([3b6d5c](https://github.com/fmoko/rustlings/commit/3b6d5c3aaa27a242a832799eb66e96897d26fde3))
+
+#### Bug Fixes
+
+* **primitive_types:** revert primitive_types4 (#296) ([b3a3351e](https://github.com/rust-lang/rustlings/commit/b3a3351e8e6a0bdee07077d7b0382953821649ae))
+* **run:**  compile clippy exercise files (#295) ([3ab084a4](https://github.com/rust-lang/rustlings/commit/3ab084a421c0f140ae83bf1fc3f47b39342e7373))
+* **conversions:**
+  * add additional test to meet exercise rules (#284) ([bc22ec3](https://github.com/fmoko/rustlings/commit/bc22ec382f843347333ef1301fc1bad773657f38))
+  * remove duplicate not done comment (#292) ([dab90f](https://github.com/fmoko/rustlings/commit/dab90f7b91a6000fe874e3d664f244048e5fa342))
+* don't hardcode documentation version for traits (#288) ([30e6af](https://github.com/fmoko/rustlings/commit/30e6af60690c326fb5d3a9b7335f35c69c09137d))
+
+#### Features
+
+*   add Option2 exercise (#290) ([86b5c08b](https://github.com/rust-lang/rustlings/commit/86b5c08b9bea1576127a7c5f599f5752072c087d))
+*   add excercise for option (#282) ([135e5d47](https://github.com/rust-lang/rustlings/commit/135e5d47a7c395aece6f6022117fb20c82f2d3d4))
+*   add new exercises for generics (#280) ([76be5e4e](https://github.com/rust-lang/rustlings/commit/76be5e4e991160f5fd9093f03ee2ba260e8f7229))
+* **ci:**  add buildkite config ([b049fa2c](https://github.com/rust-lang/rustlings/commit/b049fa2c84dba0f0c8906ac44e28fd45fba51a71))
+
+<a name="2.2.1"></a>
+### 2.2.1 (2020-02-27)
+
+#### Bug Fixes
+
+*   Re-add cloning the repo to install scripts ([3d9b03c5](https://github.com/rust-lang/rustlings/commit/3d9b03c52b8dc51b140757f6fd25ad87b5782ef5))
+
+#### Features
+
+*   Add clippy lints (#269) ([1e2fd9c9](https://github.com/rust-lang/rustlings/commit/1e2fd9c92f8cd6e389525ca1a999fca4c90b5921))
+
+<a name="2.2.0"></a>
+## 2.2.0 (2020-02-25)
+
+
+#### Bug Fixes
+
+*   Update deps to version compatable with aarch64-pc-windows (#263) ([19a93428](https://github.com/rust-lang/rustlings/commit/19a93428b3c73d994292671f829bdc8e5b7b3401))
+* **docs:**
+  * Added a necessary step to Windows installation process (#242) ([3906efcd](https://github.com/rust-lang/rustlings/commit/3906efcd52a004047b460ed548037093de3f523f))
+  * Fixed mangled sentence from book; edited for clarity (#266) ([ade52ff](https://github.com/rust-lang/rustlings/commit/ade52ffb739987287ddd5705944c8777705faed9))
+  * Updated iterators readme to account for iterators4 exercise (#273) ([bec8e3a](https://github.com/rust-lang/rustlings/commit/bec8e3a644cbd88db1c73ea5f1d8a364f4a34016))
+* **installation:**  make fatal errors more obvious (#272) ([17d0951e](https://github.com/rust-lang/rustlings/commit/17d0951e66fda8e11b204d5c4c41a0d5e22e78f7))
+* **iterators2:**
+  *  Remove reference to missing iterators2.rs (#245) ([419f7797](https://github.com/rust-lang/rustlings/commit/419f7797f294e4ce6a2b883199731b5bde77d262))
+* **as_ref_mut:** Enable a test and improve per clippy's suggestion (#256) ([dfdf809](https://github.com/rust-lang/rustlings/commit/dfdf8093ebbd4145864995627b812780de52f902))
+* **tests1:**
+  * Change test command ([fe10e06c](https://github.com/rust-lang/rustlings/commit/fe10e06c3733ddb4a21e90d09bf79bfe618e97ce)
+  * Correct test command in tests1.rs comment (#263) ([39fa7ae](https://github.com/rust-lang/rustlings/commit/39fa7ae8b70ad468da49b06f11b2383135a63bcf))
+
+#### Features
+
+*   Add variables5.rs exercise (#264) ([0c73609e](https://github.com/rust-lang/rustlings/commit/0c73609e6f2311295e95d6f96f8c747cfc4cba03))
+*   Show a completion message when watching (#253) ([d25ee55a](https://github.com/rust-lang/rustlings/commit/d25ee55a3205882d35782e370af855051b39c58c))
+*   Add type conversion and parsing exercises (#249) ([0c85dc11](https://github.com/rust-lang/rustlings/commit/0c85dc1193978b5165491b99cc4922caf8d14a65))
+*   Created consistent money unit (#258) ([fd57f8f](https://github.com/rust-lang/rustlings/commit/fd57f8f2c1da2af8ddbebbccec214e6f40f4dbab))
+*   Enable test for exercise test4 (#276) ([8b971ff](https://github.com/rust-lang/rustlings/commit/8b971ffab6079a706ac925f5917f987932b55c07))
+*   Added traits exercises (#274 but specifically #216, which originally added
+    this :heart:) ([b559cdd](https://github.com/rust-lang/rustlings/commit/b559cdd73f32c0d0cfc1feda39f82b3e3583df17))
+
+
+<a name="2.1.0"></a>
+## 2.1.0 (2019-11-27)
+
+#### Bug Fixes
+
+* add line numbers in several exercises and hints ([b565c4d3](https://github.com/rust-lang/rustlings/commit/b565c4d3e74e8e110bef201a082fa1302722a7c3))
+* **arc1:**  Fix some words in the comment ([c42c3b21](https://github.com/rust-lang/rustlings/commit/c42c3b2101df9164c8cd7bb344def921e5ba3e61))
+* **enums:**  Add link to chapter on pattern syntax (#242) ([615ce327](https://github.com/rust-lang/rustlings/commit/615ce3279800c56d89f19d218ccb7ef576624feb))
+* **primitive_types4:**
+  *  update outdated hint ([4c5189df](https://github.com/rust-lang/rustlings/commit/4c5189df2bdd9a231f6b2611919ba5aa14da0d3f))
+  *  update outdated comment ([ded2c034](https://github.com/rust-lang/rustlings/commit/ded2c034ba93fa1e3c2c2ea16b83abc1a57265e8))
+* **strings2:**  update line number in hint ([a09f684f](https://github.com/rust-lang/rustlings/commit/a09f684f05c58d239a6fc59ec5f81c2533e8b820))
+* **variables1:**  Correct wrong word in comment ([fda5a470](https://github.com/rust-lang/rustlings/commit/fda5a47069e0954f16a04e8e50945e03becb71a5))
+
+#### Features
+
+* **watch:**  show hint while watching ([8143d57b](https://github.com/rust-lang/rustlings/commit/8143d57b4e88c51341dd4a18a14c536042cc009c))
+
+<a name="2.0.0"></a>
+## 2.0.0 (2019-11-12)
+
+#### Bug Fixes
+
+* **default:**  Clarify the installation procedure ([c371b853](https://github.com/rust-lang/rustlings/commit/c371b853afa08947ddeebec0edd074b171eeaae0))
+* **info:**  Fix trailing newlines for hints ([795b6e34](https://github.com/rust-lang/rustlings/commit/795b6e348094a898e9227a14f6232f7bb94c8d31))
+* **run:**  make `run` never prompt ([4b265465](https://github.com/rust-lang/rustlings/commit/4b26546589f7d2b50455429482cf1f386ceae8b3))
+
+#### Breaking Changes
+
+*   Refactor hint system ([9bdb0a12](https://github.com/rust-lang/rustlings/commit/9bdb0a12e45a8e9f9f6a4bd4a9c172c5376c7f60))
+*   improve `watch` execution mode ([2cdd6129](https://github.com/rust-lang/rustlings/commit/2cdd61294f0d9a53775ee24ad76435bec8a21e60))
+*   Index exercises by name ([627cdc07](https://github.com/rust-lang/rustlings/commit/627cdc07d07dfe6a740e885e0ddf6900e7ec336b))
+* **run:**  makes `run` never prompt ([4b265465](https://github.com/rust-lang/rustlings/commit/4b26546589f7d2b50455429482cf1f386ceae8b3))
+
+#### Features
+
+* **cli:**  check for rustc before doing anything ([36a033b8](https://github.com/rust-lang/rustlings/commit/36a033b87a6549c1e5639c908bf7381c84f4f425))
+* **hint:**  Add test for hint ([ce9fa6eb](https://github.com/rust-lang/rustlings/commit/ce9fa6ebbfdc3e7585d488d9409797285708316f))
+
 <a name="1.5.1"></a>
 ### 1.5.1 (2019-11-11)
 

CONTRIBUTING.md

@@ -35,8 +35,11 @@ You want to make sure where in the file you add your exercise. If you're not sur
 ```diff
   ...
 + [[exercises]]
++ name = "yourTopicN"
 + path = "exercises/yourTopic/yourTopicN.rs"
 + mode = "compile"
++ hint = """
++ Some kind of useful hint for your exercise."""
   ...
 ```
 
@@ -125,4 +128,4 @@ BREAKING CHANGE: This has to be done because lorem ipsum dolor
 Once you open a Pull Request, it may be reviewed or labeled (or both) until
 the maintainers accept your change. Then, [bors](https://github.com/bors) will
 run the test suite with your changes and if it's successful, automatically
-merge it in!
+merge it in!

Cargo.lock

@@ -1,13 +1,5 @@
 # This file is automatically @generated by Cargo.
 # It is not intended for manual editing.
-[[package]]
-name = "aho-corasick"
-version = "0.6.10"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-dependencies = [
- "memchr 2.2.0 (registry+https://github.com/rust-lang/crates.io-index)",
-]
-
 [[package]]
 name = "aho-corasick"
 version = "0.7.3"
@@ -21,7 +13,7 @@ name = "ansi_term"
 version = "0.11.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 dependencies = [
- "winapi 0.3.7 (registry+https://github.com/rust-lang/crates.io-index)",
+ "winapi 0.3.8 (registry+https://github.com/rust-lang/crates.io-index)",
 ]
 
 [[package]]
@@ -42,7 +34,7 @@ source = "registry+https://github.com/rust-lang/crates.io-index"
 dependencies = [
  "libc 0.2.58 (registry+https://github.com/rust-lang/crates.io-index)",
  "termion 1.5.2 (registry+https://github.com/rust-lang/crates.io-index)",
- "winapi 0.3.7 (registry+https://github.com/rust-lang/crates.io-index)",
+ "winapi 0.3.8 (registry+https://github.com/rust-lang/crates.io-index)",
 ]
 
 [[package]]
@@ -74,17 +66,6 @@ dependencies = [
  "vec_map 0.8.1 (registry+https://github.com/rust-lang/crates.io-index)",
 ]
 
-[[package]]
-name = "clicolors-control"
-version = "0.2.0"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-dependencies = [
- "kernel32-sys 0.2.2 (registry+https://github.com/rust-lang/crates.io-index)",
- "lazy_static 0.2.11 (registry+https://github.com/rust-lang/crates.io-index)",
- "libc 0.2.58 (registry+https://github.com/rust-lang/crates.io-index)",
- "winapi 0.3.7 (registry+https://github.com/rust-lang/crates.io-index)",
-]
-
 [[package]]
 name = "clicolors-control"
 version = "1.0.0"
@@ -93,7 +74,7 @@ dependencies = [
  "atty 0.2.11 (registry+https://github.com/rust-lang/crates.io-index)",
  "lazy_static 1.3.0 (registry+https://github.com/rust-lang/crates.io-index)",
  "libc 0.2.58 (registry+https://github.com/rust-lang/crates.io-index)",
- "winapi 0.3.7 (registry+https://github.com/rust-lang/crates.io-index)",
+ "winapi 0.3.8 (registry+https://github.com/rust-lang/crates.io-index)",
 ]
 
 [[package]]
@@ -106,23 +87,7 @@ dependencies = [
 
 [[package]]
 name = "console"
-version = "0.6.2"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-dependencies = [
- "atty 0.2.11 (registry+https://github.com/rust-lang/crates.io-index)",
- "clicolors-control 0.2.0 (registry+https://github.com/rust-lang/crates.io-index)",
- "lazy_static 1.3.0 (registry+https://github.com/rust-lang/crates.io-index)",
- "libc 0.2.58 (registry+https://github.com/rust-lang/crates.io-index)",
- "parking_lot 0.8.0 (registry+https://github.com/rust-lang/crates.io-index)",
- "regex 1.1.6 (registry+https://github.com/rust-lang/crates.io-index)",
- "termios 0.3.1 (registry+https://github.com/rust-lang/crates.io-index)",
- "unicode-width 0.1.5 (registry+https://github.com/rust-lang/crates.io-index)",
- "winapi 0.3.7 (registry+https://github.com/rust-lang/crates.io-index)",
-]
-
-[[package]]
-name = "console"
-version = "0.7.5"
+version = "0.7.7"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 dependencies = [
  "atty 0.2.11 (registry+https://github.com/rust-lang/crates.io-index)",
@@ -134,7 +99,22 @@ dependencies = [
  "regex 1.1.6 (registry+https://github.com/rust-lang/crates.io-index)",
  "termios 0.3.1 (registry+https://github.com/rust-lang/crates.io-index)",
  "unicode-width 0.1.5 (registry+https://github.com/rust-lang/crates.io-index)",
- "winapi 0.3.7 (registry+https://github.com/rust-lang/crates.io-index)",
+ "winapi 0.3.8 (registry+https://github.com/rust-lang/crates.io-index)",
+]
+
+[[package]]
+name = "console"
+version = "0.8.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+dependencies = [
+ "clicolors-control 1.0.0 (registry+https://github.com/rust-lang/crates.io-index)",
+ "encode_unicode 0.3.5 (registry+https://github.com/rust-lang/crates.io-index)",
+ "lazy_static 1.3.0 (registry+https://github.com/rust-lang/crates.io-index)",
+ "libc 0.2.58 (registry+https://github.com/rust-lang/crates.io-index)",
+ "regex 1.1.6 (registry+https://github.com/rust-lang/crates.io-index)",
+ "termios 0.3.1 (registry+https://github.com/rust-lang/crates.io-index)",
+ "unicode-width 0.1.5 (registry+https://github.com/rust-lang/crates.io-index)",
+ "winapi 0.3.8 (registry+https://github.com/rust-lang/crates.io-index)",
 ]
 
 [[package]]
@@ -168,6 +148,14 @@ dependencies = [
  "redox_syscall 0.1.54 (registry+https://github.com/rust-lang/crates.io-index)",
 ]
 
+[[package]]
+name = "float-cmp"
+version = "0.4.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+dependencies = [
+ "num-traits 0.2.8 (registry+https://github.com/rust-lang/crates.io-index)",
+]
+
 [[package]]
 name = "fsevent"
 version = "0.4.0"
@@ -204,20 +192,26 @@ name = "fuchsia-zircon-sys"
 version = "0.3.3"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 
+[[package]]
+name = "glob"
+version = "0.3.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+
 [[package]]
 name = "indicatif"
-version = "0.9.0"
+version = "0.10.3"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 dependencies = [
- "console 0.7.5 (registry+https://github.com/rust-lang/crates.io-index)",
- "lazy_static 0.2.11 (registry+https://github.com/rust-lang/crates.io-index)",
+ "console 0.8.0 (registry+https://github.com/rust-lang/crates.io-index)",
+ "lazy_static 1.3.0 (registry+https://github.com/rust-lang/crates.io-index)",
+ "number_prefix 0.2.8 (registry+https://github.com/rust-lang/crates.io-index)",
  "parking_lot 0.8.0 (registry+https://github.com/rust-lang/crates.io-index)",
- "regex 0.2.11 (registry+https://github.com/rust-lang/crates.io-index)",
+ "regex 1.1.6 (registry+https://github.com/rust-lang/crates.io-index)",
 ]
 
 [[package]]
 name = "inotify"
-version = "0.6.1"
+version = "0.7.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 dependencies = [
  "bitflags 1.0.4 (registry+https://github.com/rust-lang/crates.io-index)",
@@ -256,11 +250,6 @@ dependencies = [
  "winapi-build 0.1.1 (registry+https://github.com/rust-lang/crates.io-index)",
 ]
 
-[[package]]
-name = "lazy_static"
-version = "0.2.11"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-
 [[package]]
 name = "lazy_static"
 version = "1.3.0"
@@ -343,25 +332,45 @@ source = "registry+https://github.com/rust-lang/crates.io-index"
 dependencies = [
  "cfg-if 0.1.9 (registry+https://github.com/rust-lang/crates.io-index)",
  "libc 0.2.58 (registry+https://github.com/rust-lang/crates.io-index)",
- "winapi 0.3.7 (registry+https://github.com/rust-lang/crates.io-index)",
+ "winapi 0.3.8 (registry+https://github.com/rust-lang/crates.io-index)",
 ]
 
+[[package]]
+name = "normalize-line-endings"
+version = "0.2.2"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+
 [[package]]
 name = "notify"
-version = "4.0.12"
+version = "4.0.15"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 dependencies = [
  "bitflags 1.0.4 (registry+https://github.com/rust-lang/crates.io-index)",
  "filetime 0.2.5 (registry+https://github.com/rust-lang/crates.io-index)",
  "fsevent 0.4.0 (registry+https://github.com/rust-lang/crates.io-index)",
  "fsevent-sys 2.0.1 (registry+https://github.com/rust-lang/crates.io-index)",
- "inotify 0.6.1 (registry+https://github.com/rust-lang/crates.io-index)",
- "kernel32-sys 0.2.2 (registry+https://github.com/rust-lang/crates.io-index)",
+ "inotify 0.7.0 (registry+https://github.com/rust-lang/crates.io-index)",
  "libc 0.2.58 (registry+https://github.com/rust-lang/crates.io-index)",
  "mio 0.6.19 (registry+https://github.com/rust-lang/crates.io-index)",
  "mio-extras 2.0.5 (registry+https://github.com/rust-lang/crates.io-index)",
  "walkdir 2.2.7 (registry+https://github.com/rust-lang/crates.io-index)",
- "winapi 0.3.7 (registry+https://github.com/rust-lang/crates.io-index)",
+ "winapi 0.3.8 (registry+https://github.com/rust-lang/crates.io-index)",
+]
+
+[[package]]
+name = "num-traits"
+version = "0.2.8"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+dependencies = [
+ "autocfg 0.1.4 (registry+https://github.com/rust-lang/crates.io-index)",
+]
+
+[[package]]
+name = "number_prefix"
+version = "0.2.8"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+dependencies = [
+ "num-traits 0.2.8 (registry+https://github.com/rust-lang/crates.io-index)",
 ]
 
 [[package]]
@@ -391,7 +400,7 @@ dependencies = [
  "redox_syscall 0.1.54 (registry+https://github.com/rust-lang/crates.io-index)",
  "rustc_version 0.2.3 (registry+https://github.com/rust-lang/crates.io-index)",
  "smallvec 0.6.9 (registry+https://github.com/rust-lang/crates.io-index)",
- "winapi 0.3.7 (registry+https://github.com/rust-lang/crates.io-index)",
+ "winapi 0.3.8 (registry+https://github.com/rust-lang/crates.io-index)",
 ]
 
 [[package]]
@@ -400,7 +409,10 @@ version = "1.0.1"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 dependencies = [
  "difference 2.0.0 (registry+https://github.com/rust-lang/crates.io-index)",
+ "float-cmp 0.4.0 (registry+https://github.com/rust-lang/crates.io-index)",
+ "normalize-line-endings 0.2.2 (registry+https://github.com/rust-lang/crates.io-index)",
  "predicates-core 1.0.0 (registry+https://github.com/rust-lang/crates.io-index)",
+ "regex 1.1.6 (registry+https://github.com/rust-lang/crates.io-index)",
 ]
 
 [[package]]
@@ -448,7 +460,7 @@ dependencies = [
  "rand_os 0.1.3 (registry+https://github.com/rust-lang/crates.io-index)",
  "rand_pcg 0.1.2 (registry+https://github.com/rust-lang/crates.io-index)",
  "rand_xorshift 0.1.1 (registry+https://github.com/rust-lang/crates.io-index)",
- "winapi 0.3.7 (registry+https://github.com/rust-lang/crates.io-index)",
+ "winapi 0.3.8 (registry+https://github.com/rust-lang/crates.io-index)",
 ]
 
 [[package]]
@@ -496,7 +508,7 @@ source = "registry+https://github.com/rust-lang/crates.io-index"
 dependencies = [
  "libc 0.2.58 (registry+https://github.com/rust-lang/crates.io-index)",
  "rand_core 0.4.0 (registry+https://github.com/rust-lang/crates.io-index)",
- "winapi 0.3.7 (registry+https://github.com/rust-lang/crates.io-index)",
+ "winapi 0.3.8 (registry+https://github.com/rust-lang/crates.io-index)",
 ]
 
 [[package]]
@@ -509,7 +521,7 @@ dependencies = [
  "libc 0.2.58 (registry+https://github.com/rust-lang/crates.io-index)",
  "rand_core 0.4.0 (registry+https://github.com/rust-lang/crates.io-index)",
  "rdrand 0.4.0 (registry+https://github.com/rust-lang/crates.io-index)",
- "winapi 0.3.7 (registry+https://github.com/rust-lang/crates.io-index)",
+ "winapi 0.3.8 (registry+https://github.com/rust-lang/crates.io-index)",
 ]
 
 [[package]]
@@ -550,18 +562,6 @@ dependencies = [
  "redox_syscall 0.1.54 (registry+https://github.com/rust-lang/crates.io-index)",
 ]
 
-[[package]]
-name = "regex"
-version = "0.2.11"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-dependencies = [
- "aho-corasick 0.6.10 (registry+https://github.com/rust-lang/crates.io-index)",
- "memchr 2.2.0 (registry+https://github.com/rust-lang/crates.io-index)",
- "regex-syntax 0.5.6 (registry+https://github.com/rust-lang/crates.io-index)",
- "thread_local 0.3.6 (registry+https://github.com/rust-lang/crates.io-index)",
- "utf8-ranges 1.0.2 (registry+https://github.com/rust-lang/crates.io-index)",
-]
-
 [[package]]
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@@ -574,14 +574,6 @@ dependencies = [
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 ]
 
-[[package]]
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-version = "0.5.6"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-dependencies = [
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-]
-
 [[package]]
 name = "regex-syntax"
 version = "0.6.6"
@@ -600,13 +592,16 @@ dependencies = [
 
 [[package]]
 name = "rustlings"
-version = "1.5.1"
+version = "4.2.0"
 dependencies = [
  "assert_cmd 0.11.1 (registry+https://github.com/rust-lang/crates.io-index)",
  "clap 2.33.0 (registry+https://github.com/rust-lang/crates.io-index)",
- "console 0.6.2 (registry+https://github.com/rust-lang/crates.io-index)",
- "indicatif 0.9.0 (registry+https://github.com/rust-lang/crates.io-index)",
- "notify 4.0.12 (registry+https://github.com/rust-lang/crates.io-index)",
+ "console 0.7.7 (registry+https://github.com/rust-lang/crates.io-index)",
+ "glob 0.3.0 (registry+https://github.com/rust-lang/crates.io-index)",
+ "indicatif 0.10.3 (registry+https://github.com/rust-lang/crates.io-index)",
+ "notify 4.0.15 (registry+https://github.com/rust-lang/crates.io-index)",
+ "predicates 1.0.1 (registry+https://github.com/rust-lang/crates.io-index)",
+ "regex 1.1.6 (registry+https://github.com/rust-lang/crates.io-index)",
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@@ -774,7 +769,7 @@ version = "2.2.7"
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 dependencies = [
  "same-file 1.0.4 (registry+https://github.com/rust-lang/crates.io-index)",
- "winapi 0.3.7 (registry+https://github.com/rust-lang/crates.io-index)",
+ "winapi 0.3.8 (registry+https://github.com/rust-lang/crates.io-index)",
  "winapi-util 0.1.2 (registry+https://github.com/rust-lang/crates.io-index)",
 ]
 
@@ -785,7 +780,7 @@ source = "registry+https://github.com/rust-lang/crates.io-index"
 
 [[package]]
 name = "winapi"
-version = "0.3.7"
+version = "0.3.8"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 dependencies = [
  "winapi-i686-pc-windows-gnu 0.4.0 (registry+https://github.com/rust-lang/crates.io-index)",
@@ -807,7 +802,7 @@ name = "winapi-util"
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 source = "registry+https://github.com/rust-lang/crates.io-index"
 dependencies = [
- "winapi 0.3.7 (registry+https://github.com/rust-lang/crates.io-index)",
+ "winapi 0.3.8 (registry+https://github.com/rust-lang/crates.io-index)",
 ]
 
 [[package]]
@@ -825,7 +820,6 @@ dependencies = [
 ]
 
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 "checksum aho-corasick 0.7.3 (registry+https://github.com/rust-lang/crates.io-index)" = "e6f484ae0c99fec2e858eb6134949117399f222608d84cadb3f58c1f97c2364c"
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@@ -834,27 +828,27 @@ dependencies = [
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-"checksum lazy_static 0.2.11 (registry+https://github.com/rust-lang/crates.io-index)" = "76f033c7ad61445c5b347c7382dd1237847eb1bce590fe50365dcb33d546be73"
 "checksum lazy_static 1.3.0 (registry+https://github.com/rust-lang/crates.io-index)" = "bc5729f27f159ddd61f4df6228e827e86643d4d3e7c32183cb30a1c08f604a14"
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@@ -865,7 +859,10 @@ dependencies = [
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 "checksum numtoa 0.1.0 (registry+https://github.com/rust-lang/crates.io-index)" = "b8f8bdf33df195859076e54ab11ee78a1b208382d3a26ec40d142ffc1ecc49ef"
 "checksum parking_lot 0.8.0 (registry+https://github.com/rust-lang/crates.io-index)" = "fa7767817701cce701d5585b9c4db3cdd02086398322c1d7e8bf5094a96a2ce7"
 "checksum parking_lot_core 0.5.0 (registry+https://github.com/rust-lang/crates.io-index)" = "cb88cb1cb3790baa6776844f968fea3be44956cf184fa1be5a03341f5491278c"
@@ -887,9 +884,7 @@ dependencies = [
 "checksum rdrand 0.4.0 (registry+https://github.com/rust-lang/crates.io-index)" = "678054eb77286b51581ba43620cc911abf02758c91f93f479767aed0f90458b2"
 "checksum redox_syscall 0.1.54 (registry+https://github.com/rust-lang/crates.io-index)" = "12229c14a0f65c4f1cb046a3b52047cdd9da1f4b30f8a39c5063c8bae515e252"
 "checksum redox_termios 0.1.1 (registry+https://github.com/rust-lang/crates.io-index)" = "7e891cfe48e9100a70a3b6eb652fef28920c117d366339687bd5576160db0f76"
-"checksum regex 0.2.11 (registry+https://github.com/rust-lang/crates.io-index)" = "9329abc99e39129fcceabd24cf5d85b4671ef7c29c50e972bc5afe32438ec384"
 "checksum regex 1.1.6 (registry+https://github.com/rust-lang/crates.io-index)" = "8f0a0bcab2fd7d1d7c54fa9eae6f43eddeb9ce2e7352f8518a814a4f65d60c58"
-"checksum regex-syntax 0.5.6 (registry+https://github.com/rust-lang/crates.io-index)" = "7d707a4fa2637f2dca2ef9fd02225ec7661fe01a53623c1e6515b6916511f7a7"
 "checksum regex-syntax 0.6.6 (registry+https://github.com/rust-lang/crates.io-index)" = "dcfd8681eebe297b81d98498869d4aae052137651ad7b96822f09ceb690d0a96"
 "checksum rustc_version 0.2.3 (registry+https://github.com/rust-lang/crates.io-index)" = "138e3e0acb6c9fb258b19b67cb8abd63c00679d2851805ea151465464fe9030a"
 "checksum ryu 0.2.8 (registry+https://github.com/rust-lang/crates.io-index)" = "b96a9549dc8d48f2c283938303c4b5a77aa29bfbc5b54b084fb1630408899a8f"
@@ -917,7 +912,7 @@ dependencies = [
 "checksum vec_map 0.8.1 (registry+https://github.com/rust-lang/crates.io-index)" = "05c78687fb1a80548ae3250346c3db86a80a7cdd77bda190189f2d0a0987c81a"
 "checksum walkdir 2.2.7 (registry+https://github.com/rust-lang/crates.io-index)" = "9d9d7ed3431229a144296213105a390676cc49c9b6a72bd19f3176c98e129fa1"
 "checksum winapi 0.2.8 (registry+https://github.com/rust-lang/crates.io-index)" = "167dc9d6949a9b857f3451275e911c3f44255842c1f7a76f33c55103a909087a"
-"checksum winapi 0.3.7 (registry+https://github.com/rust-lang/crates.io-index)" = "f10e386af2b13e47c89e7236a7a14a086791a2b88ebad6df9bf42040195cf770"
+"checksum winapi 0.3.8 (registry+https://github.com/rust-lang/crates.io-index)" = "8093091eeb260906a183e6ae1abdba2ef5ef2257a21801128899c3fc699229c6"
 "checksum winapi-build 0.1.1 (registry+https://github.com/rust-lang/crates.io-index)" = "2d315eee3b34aca4797b2da6b13ed88266e6d612562a0c46390af8299fc699bc"
 "checksum winapi-i686-pc-windows-gnu 0.4.0 (registry+https://github.com/rust-lang/crates.io-index)" = "ac3b87c63620426dd9b991e5ce0329eff545bccbbb34f3be09ff6fb6ab51b7b6"
 "checksum winapi-util 0.1.2 (registry+https://github.com/rust-lang/crates.io-index)" = "7168bab6e1daee33b4557efd0e95d5ca70a03706d39fa5f3fe7a236f584b03c9"

Cargo.toml

@@ -1,15 +1,16 @@
 [package]
 name = "rustlings"
-version = "1.5.1"
-authors = ["Marisa <mokou@posteo.de>", "Carol (Nichols || Goulding) <carol.nichols@gmail.com"]
+version = "4.2.0"
+authors = ["Marisa <mokou@posteo.de>", "Carol (Nichols || Goulding) <carol.nichols@gmail.com>"]
 edition = "2018"
 
 [dependencies]
 clap = "2.32.0"
-indicatif = "0.9.0"
-console = "0.6.2"
-notify = "4.0.0"
+indicatif = "0.10.3"
+console = "0.7.7"
+notify = "4.0.15"
 toml = "0.4.10"
+regex = "1.1.6"
 serde = {version = "1.0.10", features = ["derive"]}
 
 [[bin]]
@@ -18,3 +19,5 @@ path = "src/main.rs"
 
 [dev-dependencies]
 assert_cmd = "0.11.0"
+predicates = "1.0.1"
+glob = "0.3.0"

README.md

@@ -1,12 +1,15 @@
 ![crab pet](https://i.imgur.com/LbZJgmm.gif)
+<!-- ALL-CONTRIBUTORS-BADGE:START - Do not remove or modify this section -->
+[![All Contributors](https://img.shields.io/badge/all_contributors-68-orange.svg?style=flat-square)](#contributors-)
+<!-- ALL-CONTRIBUTORS-BADGE:END -->
 
-# rustlings 🦀❤️
+# rustlings 🦀❤️ [![Build status](https://badge.buildkite.com/7af93d81dc522c67a1ec8e33ff5705861b1cb36360b774807f.svg)](https://buildkite.com/mokou/rustlings)
 
 Greetings and welcome to `rustlings`. This project contains small exercises to get you used to reading and writing Rust code. This includes reading and responding to compiler messages!
 
 _...looking for the old, web-based version of Rustlings? Try [here](https://github.com/rust-lang/rustlings/tree/rustlings-1)_
 
-Alternatively, for a first-time Rust learner, there's several other resources:
+Alternatively, for a first-time Rust learner, there are several other resources:
 
 - [The Book](https://doc.rust-lang.org/book/index.html) - The most comprehensive resource for learning Rust, but a bit theoretical sometimes. You will be using this along with Rustlings!
 - [Rust By Example](https://doc.rust-lang.org/rust-by-example/index.html) - Learn Rust by solving little exercises! It's almost like `rustlings`, but online
@@ -15,8 +18,6 @@ Alternatively, for a first-time Rust learner, there's several other resources:
 
 _Note: If you're on MacOS, make sure you've installed Xcode and its developer tools by typing `xcode-select --install`._
 
-_Note: If you have Xcode 10+ installed, you also need to install the package file found at `/Library/Developer/CommandLineTools/Packages/macOS_SDK_headers_for_macOS_10.14.pkg`._
-
 You will need to have Rust installed. You can get it by visiting https://rustup.rs. This'll also install Cargo, Rust's package/project manager.
 
 ## MacOS/Linux
@@ -33,14 +34,26 @@ This will install Rustlings and give you access to the `rustlings` command. Run
 
 ## Windows
 
-You can run:
+In PowerShell, set `ExecutionPolicy` to `RemoteSigned`:
 
 ```ps
-Invoke-WebRequest https://git.io/rustlings-win | Select-Object -ExpandProperty Content | Out-File $env:TMP/install_rustlings.ps1; Unblock-File $env:TMP/install_rustlings.ps1; Invoke-Expression $env:TMP/install_rustlings.ps1
+Set-ExecutionPolicy RemoteSigned
+```
+
+Then, you can run:
+
+```ps
+Start-BitsTransfer -Source https://git.io/rustlings-win -Destination $env:TMP/install_rustlings.ps1; Unblock-File $env:TMP/install_rustlings.ps1; Invoke-Expression $env:TMP/install_rustlings.ps1
 ```
 
 To install Rustlings. Same as on MacOS/Linux, you will have access to the `rustlings` command after it.
 
+## Browser:
+
+[Run on Repl.it](https://repl.it/github/rust-lang/rustlings)
+
+[Open in Gitpod](https://gitpod.io/#https://github.com/rust-lang/rustlings)
+
 ## Manually
 
 Basically: Clone the repository, checkout to the latest tag, run `cargo install`.
@@ -48,7 +61,7 @@ Basically: Clone the repository, checkout to the latest tag, run `cargo install`
 ```bash
 git clone https://github.com/rust-lang/rustlings
 cd rustlings
-git checkout tags/1.5.1 # or whatever the latest version is (find out at https://github.com/rust-lang/rustlings/releases/latest)
+git checkout tags/4.2.0 # or whatever the latest version is (find out at https://github.com/rust-lang/rustlings/releases/latest)
 cargo install --force --path .
 ```
 
@@ -63,7 +76,7 @@ Then, same as above, run `rustlings` to get started.
 
 The exercises are sorted by topic and can be found in the subdirectory `rustlings/exercises/<topic>`. For every topic there is an additional README file with some resources to get you started on the topic. We really recommend that you have a look at them before you start.
 
-The task is simple. Most exercises contain an error that keep it from compiling, and it's up to you to fix it! Some exercises are also run as tests, but rustlings handles them all the same. To run the exercises in the recommended order, execute:
+The task is simple. Most exercises contain an error that keeps them from compiling, and it's up to you to fix it! Some exercises are also run as tests, but rustlings handles them all the same. To run the exercises in the recommended order, execute:
 
 ```bash
 rustlings watch
@@ -80,14 +93,30 @@ This will do the same as watch, but it'll quit after running.
 In case you want to go by your own order, or want to only verify a single exercise, you can run:
 
 ```bash
-rustlings run exercises/path/to/exercise.rs
+rustlings run myExercise1
 ```
 
-In case you get stuck, there is usually a hint at the bottom of each exercise.
+In case you get stuck, you can run the following command to get a hint for your
+exercise:
+
+``` bash
+rustlings hint myExercise1
+```
 
 ## Testing yourself
 
-After every couple of sections, there will be a test that'll test your knowledge on a bunch of sections at once. These tests are found in `exercises/testN.rs`.
+After every couple of sections, there will be a quiz that'll test your knowledge on a bunch of sections at once. These quizzes are found in `exercises/quizN.rs`.
+
+## Continuing On
+
+Once you've completed Rustlings, put your new knowledge to good use! Continue practicing your Rust skills by building your own projects, contributing to Rustlings, or finding other open-source projects to contribute to.
+
+If you'd like to uninstall Rustlings, you can do so by invoking cargo and removing the rustlings directory:
+
+```bash
+cargo uninstall rustlings
+rm -r rustlings/ # or on Windows: rmdir /s rustlings
+```
 
 ## Completion
 
@@ -111,7 +140,104 @@ If you are interested in improving or adding new ones, please feel free to contr
 
 See [CONTRIBUTING.md](./CONTRIBUTING.md).
 
-## Credits
+## Contributors ✨
 
-`rustlings` was originally written by [Carol](https://github.com/carols10cents)!
+Thanks goes to these wonderful people ([emoji key](https://allcontributors.org/docs/en/emoji-key)):
 
+<!-- ALL-CONTRIBUTORS-LIST:START - Do not remove or modify this section -->
+<!-- prettier-ignore-start -->
+<!-- markdownlint-disable -->
+<table>
+  <tr>
+    <td align="center"><a href="http://carol-nichols.com"><img src="https://avatars2.githubusercontent.com/u/193874?v=4" width="100px;" alt=""/><br /><sub><b>Carol (Nichols &#124;&#124; Goulding)</b></sub></a><br /><a href="https://github.com/rust-lang/rustlings/commits?author=carols10cents" title="Code">💻</a> <a href="#content-carols10cents" title="Content">🖋</a></td>
+    <td align="center"><a href="https://twitter.com/QuietMisdreavus"><img src="https://avatars2.githubusercontent.com/u/5217170?v=4" width="100px;" alt=""/><br /><sub><b>QuietMisdreavus</b></sub></a><br /><a href="https://github.com/rust-lang/rustlings/commits?author=QuietMisdreavus" title="Code">💻</a> <a href="#content-QuietMisdreavus" title="Content">🖋</a></td>
+    <td align="center"><a href="https://github.com/robertlugg"><img src="https://avatars0.githubusercontent.com/u/6054540?v=4" width="100px;" alt=""/><br /><sub><b>Robert M Lugg</b></sub></a><br /><a href="#content-robertlugg" title="Content">🖋</a></td>
+    <td align="center"><a href="https://hynek.me/about/"><img src="https://avatars3.githubusercontent.com/u/41240?v=4" width="100px;" alt=""/><br /><sub><b>Hynek Schlawack</b></sub></a><br /><a href="https://github.com/rust-lang/rustlings/commits?author=hynek" title="Code">💻</a></td>
+    <td align="center"><a href="https://spacekookie.de"><img src="https://avatars0.githubusercontent.com/u/7669898?v=4" width="100px;" alt=""/><br /><sub><b>Katharina Fey</b></sub></a><br /><a href="https://github.com/rust-lang/rustlings/commits?author=spacekookie" title="Code">💻</a></td>
+    <td align="center"><a href="https://github.com/lukabavdaz"><img src="https://avatars0.githubusercontent.com/u/9624558?v=4" width="100px;" alt=""/><br /><sub><b>lukabavdaz</b></sub></a><br /><a href="https://github.com/rust-lang/rustlings/commits?author=lukabavdaz" title="Code">💻</a> <a href="#content-lukabavdaz" title="Content">🖋</a></td>
+    <td align="center"><a href="http://vestera.as"><img src="https://avatars2.githubusercontent.com/u/4187449?v=4" width="100px;" alt=""/><br /><sub><b>Erik Vesteraas</b></sub></a><br /><a href="https://github.com/rust-lang/rustlings/commits?author=evestera" title="Code">💻</a></td>
+    <td align="center"><a href="https://github.com/Delet0r"><img src="https://avatars1.githubusercontent.com/u/23195618?v=4" width="100px;" alt=""/><br /><sub><b>delet0r</b></sub></a><br /><a href="https://github.com/rust-lang/rustlings/commits?author=Delet0r" title="Code">💻</a></td>
+  </tr>
+  <tr>
+    <td align="center"><a href="http://phinary.ca"><img src="https://avatars1.githubusercontent.com/u/10522375?v=4" width="100px;" alt=""/><br /><sub><b>Shaun Bennett</b></sub></a><br /><a href="https://github.com/rust-lang/rustlings/commits?author=shaunbennett" title="Code">💻</a></td>
+    <td align="center"><a href="https://github.com/abagshaw"><img src="https://avatars2.githubusercontent.com/u/8594541?v=4" width="100px;" alt=""/><br /><sub><b>Andrew Bagshaw</b></sub></a><br /><a href="https://github.com/rust-lang/rustlings/commits?author=abagshaw" title="Code">💻</a></td>
+    <td align="center"><a href="https://ai6ua.net/"><img src="https://avatars2.githubusercontent.com/u/175578?v=4" width="100px;" alt=""/><br /><sub><b>Kyle Isom</b></sub></a><br /><a href="https://github.com/rust-lang/rustlings/commits?author=kisom" title="Code">💻</a></td>
+    <td align="center"><a href="https://github.com/ColinPitrat"><img src="https://avatars3.githubusercontent.com/u/1541863?v=4" width="100px;" alt=""/><br /><sub><b>Colin Pitrat</b></sub></a><br /><a href="https://github.com/rust-lang/rustlings/commits?author=ColinPitrat" title="Code">💻</a></td>
+    <td align="center"><a href="https://zacanger.com"><img src="https://avatars3.githubusercontent.com/u/12520493?v=4" width="100px;" alt=""/><br /><sub><b>Zac Anger</b></sub></a><br /><a href="https://github.com/rust-lang/rustlings/commits?author=zacanger" title="Code">💻</a></td>
+    <td align="center"><a href="https://github.com/mgeier"><img src="https://avatars1.githubusercontent.com/u/705404?v=4" width="100px;" alt=""/><br /><sub><b>Matthias Geier</b></sub></a><br /><a href="https://github.com/rust-lang/rustlings/commits?author=mgeier" title="Code">💻</a></td>
+    <td align="center"><a href="https://github.com/cjpearce"><img src="https://avatars1.githubusercontent.com/u/3453268?v=4" width="100px;" alt=""/><br /><sub><b>Chris Pearce</b></sub></a><br /><a href="https://github.com/rust-lang/rustlings/commits?author=cjpearce" title="Code">💻</a></td>
+    <td align="center"><a href="https://yvan-sraka.github.io"><img src="https://avatars2.githubusercontent.com/u/705213?v=4" width="100px;" alt=""/><br /><sub><b>Yvan Sraka</b></sub></a><br /><a href="https://github.com/rust-lang/rustlings/commits?author=yvan-sraka" title="Code">💻</a></td>
+  </tr>
+  <tr>
+    <td align="center"><a href="https://github.com/dendi239"><img src="https://avatars3.githubusercontent.com/u/16478650?v=4" width="100px;" alt=""/><br /><sub><b>Denys Smirnov</b></sub></a><br /><a href="https://github.com/rust-lang/rustlings/commits?author=dendi239" title="Code">💻</a></td>
+    <td align="center"><a href="https://github.com/eddyp"><img src="https://avatars2.githubusercontent.com/u/123772?v=4" width="100px;" alt=""/><br /><sub><b>eddyp</b></sub></a><br /><a href="https://github.com/rust-lang/rustlings/commits?author=eddyp" title="Code">💻</a></td>
+    <td align="center"><a href="http://about.me/BrianKung"><img src="https://avatars1.githubusercontent.com/u/2836167?v=4" width="100px;" alt=""/><br /><sub><b>Brian Kung</b></sub></a><br /><a href="https://github.com/rust-lang/rustlings/commits?author=briankung" title="Code">💻</a> <a href="#content-briankung" title="Content">🖋</a></td>
+    <td align="center"><a href="https://rcousineau.gitlab.io"><img src="https://avatars3.githubusercontent.com/u/281039?v=4" width="100px;" alt=""/><br /><sub><b>Russell</b></sub></a><br /><a href="https://github.com/rust-lang/rustlings/commits?author=miller-time" title="Code">💻</a></td>
+    <td align="center"><a href="http://danwilhelm.com"><img src="https://avatars3.githubusercontent.com/u/6137185?v=4" width="100px;" alt=""/><br /><sub><b>Dan Wilhelm</b></sub></a><br /><a href="https://github.com/rust-lang/rustlings/commits?author=danwilhelm" title="Documentation">📖</a></td>
+    <td align="center"><a href="https://github.com/Jesse-Cameron"><img src="https://avatars3.githubusercontent.com/u/3723654?v=4" width="100px;" alt=""/><br /><sub><b>Jesse</b></sub></a><br /><a href="https://github.com/rust-lang/rustlings/commits?author=Jesse-Cameron" title="Code">💻</a> <a href="#content-Jesse-Cameron" title="Content">🖋</a></td>
+    <td align="center"><a href="https://github.com/MrFroop"><img src="https://avatars3.githubusercontent.com/u/196700?v=4" width="100px;" alt=""/><br /><sub><b>Fredrik Jambrén</b></sub></a><br /><a href="https://github.com/rust-lang/rustlings/commits?author=MrFroop" title="Code">💻</a></td>
+    <td align="center"><a href="https://github.com/petemcfarlane"><img src="https://avatars3.githubusercontent.com/u/3472717?v=4" width="100px;" alt=""/><br /><sub><b>Pete McFarlane</b></sub></a><br /><a href="#content-petemcfarlane" title="Content">🖋</a></td>
+  </tr>
+  <tr>
+    <td align="center"><a href="https://github.com/nkanderson"><img src="https://avatars0.githubusercontent.com/u/4128825?v=4" width="100px;" alt=""/><br /><sub><b>nkanderson</b></sub></a><br /><a href="https://github.com/rust-lang/rustlings/commits?author=nkanderson" title="Code">💻</a> <a href="#content-nkanderson" title="Content">🖋</a></td>
+    <td align="center"><a href="https://github.com/ajaxm"><img src="https://avatars0.githubusercontent.com/u/13360138?v=4" width="100px;" alt=""/><br /><sub><b>Ajax M</b></sub></a><br /><a href="https://github.com/rust-lang/rustlings/commits?author=ajaxm" title="Documentation">📖</a></td>
+    <td align="center"><a href="https://dylnuge.com"><img src="https://avatars2.githubusercontent.com/u/118624?v=4" width="100px;" alt=""/><br /><sub><b>Dylan Nugent</b></sub></a><br /><a href="#content-Dylnuge" title="Content">🖋</a></td>
+    <td align="center"><a href="https://github.com/vyaslav"><img src="https://avatars0.githubusercontent.com/u/1385427?v=4" width="100px;" alt=""/><br /><sub><b>vyaslav</b></sub></a><br /><a href="https://github.com/rust-lang/rustlings/commits?author=vyaslav" title="Code">💻</a> <a href="#content-vyaslav" title="Content">🖋</a></td>
+    <td align="center"><a href="https://join.sfxd.org"><img src="https://avatars1.githubusercontent.com/u/17297466?v=4" width="100px;" alt=""/><br /><sub><b>George</b></sub></a><br /><a href="https://github.com/rust-lang/rustlings/commits?author=gdoenlen" title="Code">💻</a></td>
+    <td align="center"><a href="https://github.com/nyxtom"><img src="https://avatars2.githubusercontent.com/u/222763?v=4" width="100px;" alt=""/><br /><sub><b>Thomas Holloway</b></sub></a><br /><a href="https://github.com/rust-lang/rustlings/commits?author=nyxtom" title="Code">💻</a> <a href="#content-nyxtom" title="Content">🖋</a></td>
+    <td align="center"><a href="https://github.com/workingjubilee"><img src="https://avatars1.githubusercontent.com/u/46493976?v=4" width="100px;" alt=""/><br /><sub><b>Jubilee</b></sub></a><br /><a href="https://github.com/rust-lang/rustlings/commits?author=workingjubilee" title="Code">💻</a></td>
+    <td align="center"><a href="https://github.com/WofWca"><img src="https://avatars1.githubusercontent.com/u/39462442?v=4" width="100px;" alt=""/><br /><sub><b>WofWca</b></sub></a><br /><a href="https://github.com/rust-lang/rustlings/commits?author=WofWca" title="Code">💻</a></td>
+  </tr>
+  <tr>
+    <td align="center"><a href="https://github.com/jrvidal"><img src="https://avatars0.githubusercontent.com/u/1636604?v=4" width="100px;" alt=""/><br /><sub><b>Roberto Vidal</b></sub></a><br /><a href="https://github.com/rust-lang/rustlings/commits?author=jrvidal" title="Code">💻</a> <a href="https://github.com/rust-lang/rustlings/commits?author=jrvidal" title="Documentation">📖</a> <a href="#ideas-jrvidal" title="Ideas, Planning, & Feedback">🤔</a> <a href="#maintenance-jrvidal" title="Maintenance">🚧</a></td>
+    <td align="center"><a href="https://github.com/jensim"><img src="https://avatars0.githubusercontent.com/u/3663856?v=4" width="100px;" alt=""/><br /><sub><b>Jens</b></sub></a><br /><a href="https://github.com/rust-lang/rustlings/commits?author=jensim" title="Documentation">📖</a></td>
+    <td align="center"><a href="http://rahatah.me/d"><img src="https://avatars3.githubusercontent.com/u/3174006?v=4" width="100px;" alt=""/><br /><sub><b>Rahat Ahmed</b></sub></a><br /><a href="https://github.com/rust-lang/rustlings/commits?author=rahatarmanahmed" title="Documentation">📖</a></td>
+    <td align="center"><a href="https://github.com/AbdouSeck"><img src="https://avatars2.githubusercontent.com/u/6490055?v=4" width="100px;" alt=""/><br /><sub><b>Abdou Seck</b></sub></a><br /><a href="https://github.com/rust-lang/rustlings/commits?author=AbdouSeck" title="Code">💻</a> <a href="#content-AbdouSeck" title="Content">🖋</a> <a href="https://github.com/rust-lang/rustlings/pulls?q=is%3Apr+reviewed-by%3AAbdouSeck" title="Reviewed Pull Requests">👀</a></td>
+    <td align="center"><a href="https://codehearts.com"><img src="https://avatars0.githubusercontent.com/u/2885412?v=4" width="100px;" alt=""/><br /><sub><b>Katie</b></sub></a><br /><a href="https://github.com/rust-lang/rustlings/commits?author=codehearts" title="Code">💻</a></td>
+    <td align="center"><a href="https://github.com/Socratides"><img src="https://avatars3.githubusercontent.com/u/27732983?v=4" width="100px;" alt=""/><br /><sub><b>Socrates</b></sub></a><br /><a href="https://github.com/rust-lang/rustlings/commits?author=Socratides" title="Documentation">📖</a></td>
+    <td align="center"><a href="https://github.com/gnodarse"><img src="https://avatars3.githubusercontent.com/u/46761795?v=4" width="100px;" alt=""/><br /><sub><b>gnodarse</b></sub></a><br /><a href="#content-gnodarse" title="Content">🖋</a></td>
+    <td align="center"><a href="https://github.com/harrisonmetz"><img src="https://avatars1.githubusercontent.com/u/7883408?v=4" width="100px;" alt=""/><br /><sub><b>Harrison Metzger</b></sub></a><br /><a href="https://github.com/rust-lang/rustlings/commits?author=harrisonmetz" title="Code">💻</a></td>
+  </tr>
+  <tr>
+    <td align="center"><a href="https://github.com/TorbenJ"><img src="https://avatars2.githubusercontent.com/u/9077102?v=4" width="100px;" alt=""/><br /><sub><b>Torben Jonas</b></sub></a><br /><a href="https://github.com/rust-lang/rustlings/commits?author=TorbenJ" title="Code">💻</a> <a href="#content-TorbenJ" title="Content">🖋</a></td>
+    <td align="center"><a href="http://paulbissex.com/"><img src="https://avatars0.githubusercontent.com/u/641?v=4" width="100px;" alt=""/><br /><sub><b>Paul Bissex</b></sub></a><br /><a href="https://github.com/rust-lang/rustlings/commits?author=pbx" title="Documentation">📖</a></td>
+    <td align="center"><a href="https://github.com/sjmann"><img src="https://avatars0.githubusercontent.com/u/6589896?v=4" width="100px;" alt=""/><br /><sub><b>Steven Mann</b></sub></a><br /><a href="https://github.com/rust-lang/rustlings/commits?author=sjmann" title="Code">💻</a> <a href="#content-sjmann" title="Content">🖋</a></td>
+    <td align="center"><a href="https://smmdb.net/"><img src="https://avatars2.githubusercontent.com/u/5855071?v=4" width="100px;" alt=""/><br /><sub><b>Mario Reder</b></sub></a><br /><a href="https://github.com/rust-lang/rustlings/commits?author=Tarnadas" title="Code">💻</a> <a href="#content-Tarnadas" title="Content">🖋</a></td>
+    <td align="center"><a href="https://keybase.io/skim"><img src="https://avatars0.githubusercontent.com/u/47347?v=4" width="100px;" alt=""/><br /><sub><b>skim</b></sub></a><br /><a href="https://github.com/rust-lang/rustlings/commits?author=sl4m" title="Code">💻</a></td>
+    <td align="center"><a href="https://github.com/sanjaykdragon"><img src="https://avatars1.githubusercontent.com/u/10261698?v=4" width="100px;" alt=""/><br /><sub><b>Sanjay K</b></sub></a><br /><a href="https://github.com/rust-lang/rustlings/commits?author=sanjaykdragon" title="Code">💻</a> <a href="#content-sanjaykdragon" title="Content">🖋</a></td>
+    <td align="center"><a href="http://www.rohanjain.in"><img src="https://avatars1.githubusercontent.com/u/343499?v=4" width="100px;" alt=""/><br /><sub><b>Rohan Jain</b></sub></a><br /><a href="https://github.com/rust-lang/rustlings/commits?author=crodjer" title="Code">💻</a></td>
+    <td align="center"><a href="https://www.saidaspen.se"><img src="https://avatars1.githubusercontent.com/u/7727687?v=4" width="100px;" alt=""/><br /><sub><b>Said Aspen</b></sub></a><br /><a href="https://github.com/rust-lang/rustlings/commits?author=saidaspen" title="Code">💻</a> <a href="#content-saidaspen" title="Content">🖋</a></td>
+  </tr>
+  <tr>
+    <td align="center"><a href="https://github.com/uce"><img src="https://avatars3.githubusercontent.com/u/1756620?v=4" width="100px;" alt=""/><br /><sub><b>Ufuk Celebi</b></sub></a><br /><a href="https://github.com/rust-lang/rustlings/commits?author=uce" title="Code">💻</a></td>
+    <td align="center"><a href="https://github.com/lebedevsergey"><img src="https://avatars2.githubusercontent.com/u/7325764?v=4" width="100px;" alt=""/><br /><sub><b>lebedevsergey</b></sub></a><br /><a href="https://github.com/rust-lang/rustlings/commits?author=lebedevsergey" title="Documentation">📖</a></td>
+    <td align="center"><a href="https://github.com/avrong"><img src="https://avatars2.githubusercontent.com/u/6342851?v=4" width="100px;" alt=""/><br /><sub><b>Aleksei Trifonov</b></sub></a><br /><a href="#content-avrong" title="Content">🖋</a></td>
+    <td align="center"><a href="https://drn.ie"><img src="https://avatars2.githubusercontent.com/u/411136?v=4" width="100px;" alt=""/><br /><sub><b>Darren Meehan</b></sub></a><br /><a href="#content-Darrenmeehan" title="Content">🖋</a></td>
+    <td align="center"><a href="https://github.com/jihchi"><img src="https://avatars1.githubusercontent.com/u/87983?v=4" width="100px;" alt=""/><br /><sub><b>Jihchi Lee</b></sub></a><br /><a href="#content-jihchi" title="Content">🖋</a></td>
+    <td align="center"><a href="https://github.com/bertonha"><img src="https://avatars3.githubusercontent.com/u/1225902?v=4" width="100px;" alt=""/><br /><sub><b>Christofer Bertonha</b></sub></a><br /><a href="#content-bertonha" title="Content">🖋</a></td>
+    <td align="center"><a href="https://github.com/apatniv"><img src="https://avatars2.githubusercontent.com/u/22565917?v=4" width="100px;" alt=""/><br /><sub><b>Vivek Bharath Akupatni</b></sub></a><br /><a href="https://github.com/rust-lang/rustlings/commits?author=apatniv" title="Code">💻</a> <a href="https://github.com/rust-lang/rustlings/commits?author=apatniv" title="Tests">⚠️</a></td>
+    <td align="center"><a href="https://github.com/DiD92"><img src="https://avatars3.githubusercontent.com/u/6002416?v=4" width="100px;" alt=""/><br /><sub><b>Dídac Sementé Fernández</b></sub></a><br /><a href="https://github.com/rust-lang/rustlings/commits?author=DiD92" title="Code">💻</a> <a href="#content-DiD92" title="Content">🖋</a></td>
+  </tr>
+  <tr>
+    <td align="center"><a href="https://github.com/wrobstory"><img src="https://avatars3.githubusercontent.com/u/2601457?v=4" width="100px;" alt=""/><br /><sub><b>Rob Story</b></sub></a><br /><a href="https://github.com/rust-lang/rustlings/commits?author=wrobstory" title="Code">💻</a></td>
+    <td align="center"><a href="https://github.com/siobhanjacobson"><img src="https://avatars2.githubusercontent.com/u/28983835?v=4" width="100px;" alt=""/><br /><sub><b>Siobhan Jacobson</b></sub></a><br /><a href="https://github.com/rust-lang/rustlings/commits?author=siobhanjacobson" title="Code">💻</a></td>
+    <td align="center"><a href="https://www.linkedin.com/in/evancarroll/"><img src="https://avatars2.githubusercontent.com/u/19922?v=4" width="100px;" alt=""/><br /><sub><b>Evan Carroll</b></sub></a><br /><a href="#content-EvanCarroll" title="Content">🖋</a></td>
+    <td align="center"><a href="http://www.jawaadmahmood.com"><img src="https://avatars3.githubusercontent.com/u/95606?v=4" width="100px;" alt=""/><br /><sub><b>Jawaad Mahmood</b></sub></a><br /><a href="#content-jmahmood" title="Content">🖋</a></td>
+    <td align="center"><a href="https://github.com/GaurangTandon"><img src="https://avatars1.githubusercontent.com/u/6308683?v=4" width="100px;" alt=""/><br /><sub><b>Gaurang Tandon</b></sub></a><br /><a href="#content-GaurangTandon" title="Content">🖋</a></td>
+    <td align="center"><a href="https://github.com/dev-cyprium"><img src="https://avatars1.githubusercontent.com/u/6002628?v=4" width="100px;" alt=""/><br /><sub><b>Stefan Kupresak</b></sub></a><br /><a href="#content-dev-cyprium" title="Content">🖋</a></td>
+    <td align="center"><a href="https://github.com/greg-el"><img src="https://avatars3.githubusercontent.com/u/45019882?v=4" width="100px;" alt=""/><br /><sub><b>Greg Leonard</b></sub></a><br /><a href="#content-greg-el" title="Content">🖋</a></td>
+    <td align="center"><a href="https://ryanpcmcquen.org"><img src="https://avatars3.githubusercontent.com/u/772937?v=4" width="100px;" alt=""/><br /><sub><b>Ryan McQuen</b></sub></a><br /><a href="https://github.com/rust-lang/rustlings/commits?author=ryanpcmcquen" title="Code">💻</a></td>
+  </tr>
+  <tr>
+    <td align="center"><a href="https://github.com/AnnikaCodes"><img src="https://avatars3.githubusercontent.com/u/56906084?v=4" width="100px;" alt=""/><br /><sub><b>Annika</b></sub></a><br /><a href="https://github.com/rust-lang/rustlings/pulls?q=is%3Apr+reviewed-by%3AAnnikaCodes" title="Reviewed Pull Requests">👀</a></td>
+    <td align="center"><a href="https://darnuria.eu"><img src="https://avatars1.githubusercontent.com/u/2827553?v=4" width="100px;" alt=""/><br /><sub><b>Axel Viala</b></sub></a><br /><a href="https://github.com/rust-lang/rustlings/commits?author=darnuria" title="Code">💻</a></td>
+    <td align="center"><a href="https://sazid.github.io"><img src="https://avatars1.githubusercontent.com/u/2370167?v=4" width="100px;" alt=""/><br /><sub><b>Mohammed Sazid Al Rashid</b></sub></a><br /><a href="#content-sazid" title="Content">🖋</a> <a href="https://github.com/rust-lang/rustlings/commits?author=sazid" title="Code">💻</a></td>
+    <td align="center"><a href="https://codingthemsoftly.com"><img src="https://avatars1.githubusercontent.com/u/17479099?v=4" width="100px;" alt=""/><br /><sub><b>Caleb Webber</b></sub></a><br /><a href="#maintenance-seeplusplus" title="Maintenance">🚧</a></td>
+  </tr>
+</table>
+
+<!-- markdownlint-enable -->
+<!-- prettier-ignore-end -->
+<!-- ALL-CONTRIBUTORS-LIST:END -->
+
+This project follows the [all-contributors](https://github.com/all-contributors/all-contributors) specification. Contributions of any kind welcome!

buildkite.yml

@@ -0,0 +1,5 @@
+steps:
+  - label: "Test with stable"
+    command: rustup run stable cargo test
+  - label: "Test with beta"
+    command: rustup run beta cargo test

default_out.txt

@@ -7,7 +7,8 @@ Let's make sure you're up to speed:
 - You have `~/.cargo/bin` added to your PATH variable
 - You have cloned this repository (https://github.com/rust-lang/rustlings)
 - You have installed Rust language support for your editor
-- You have locally installed the `rustlings` command by running:
+- You have locally installed the `rustlings` command by running an
+  installation script or manually executing:
 
 cargo install --force --path .
 
@@ -15,4 +16,4 @@ If you've done all of this (or even most of it), congrats! You're ready
 to start working with Rust.
 
 To get started, run `rustlings watch` in order to get the first exercise.
-Make sure to have your editor open!
+Make sure to have your editor open!

exercises/clippy/README.md

@@ -0,0 +1,8 @@
+### Clippy
+
+The Clippy tool is a collection of lints to analyze your code so you can catch common mistakes and improve your Rust code.
+
+If you used the installation script for Rustlings, Clippy should be already installed.
+If not you can install it manually via `rustup component add clippy`.
+
+For more information about Clippy lints, please see [their documentation page](https://rust-lang.github.io/rust-clippy/master/).

exercises/clippy/clippy1.rs

@@ -0,0 +1,17 @@
+// clippy1.rs
+// The Clippy tool is a collection of lints to analyze your code
+// so you can catch common mistakes and improve your Rust code.
+//
+// For these exercises the code will fail to compile when there are clippy warnings
+// check clippy's suggestions from the output to solve the exercise.
+// Execute `rustlings hint clippy1` for hints :)
+
+// I AM NOT DONE
+
+fn main() {
+    let x = 1.2331f64;
+    let y = 1.2332f64;
+    if y != x {
+        println!("Success!");
+    }
+}

exercises/clippy/clippy2.rs

@@ -0,0 +1,13 @@
+// clippy2.rs
+// Make me compile! Execute `rustlings hint clippy2` for hints :)
+
+// I AM NOT DONE
+
+fn main() {
+    let mut res = 42;
+    let option = Some(12);
+    for x in option {
+        res += x;
+    }
+    println!("{}", res);
+}

exercises/collections/README.md

@@ -0,0 +1,20 @@
+### Collections
+
+Rust’s standard library includes a number of very useful data
+structures called collections. Most other data types represent one
+specific value, but collections can contain multiple values. Unlike
+the built-in array and tuple types, the data these collections point
+to is stored on the heap, which means the amount of data does not need
+to be known at compile time and can grow or shrink as the program
+runs.
+
+This exercise will get you familiar with two fundamental data
+structures that are used very often in Rust programs:
+
+* A *vector* allows you to store a variable number of values next to
+  each other.
+* A *hash map* allows you to associate a value with a particular key.
+  You may also know this by the names *map* in C++, *dictionary* in
+  Python or an *associative array* in other languages.
+
+[Rust book chapter](https://doc.rust-lang.org/stable/book/ch08-01-vectors.html)

exercises/collections/hashmap1.rs

@@ -0,0 +1,46 @@
+// hashmap1.rs
+// A basket of fruits in the form of a hash map needs to be defined.
+// The key represents the name of the fruit and the value represents
+// how many of that particular fruit is in the basket. You have to put
+// at least three different types of fruits (e.g apple, banana, mango)
+// in the basket and the total count of all the fruits should be at
+// least five.
+//
+// Make me compile and pass the tests!
+//
+// Execute the command `rustlings hint collections3` if you need
+// hints.
+
+// I AM NOT DONE
+
+use std::collections::HashMap;
+
+fn fruit_basket() -> HashMap<String, u32> {
+    let mut basket = // TODO: declare your hash map here.
+
+    // Two bananas are already given for you :)
+    basket.insert(String::from("banana"), 2);
+
+    // TODO: Put more fruits in your basket here.
+
+    basket
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+
+    #[test]
+    fn at_least_three_types_of_fruits() {
+        let basket = fruit_basket();
+        assert!(basket.len() >= 3);
+    }
+
+    #[test]
+    fn at_least_five_fruits() {
+        let basket = fruit_basket();
+        assert!(basket
+            .values()
+            .sum::<u32>() >= 5);
+    }
+}

exercises/collections/hashmap2.rs

@@ -0,0 +1,83 @@
+// hashmap2.rs
+
+// A basket of fruits in the form of a hash map is given. The key
+// represents the name of the fruit and the value represents how many
+// of that particular fruit is in the basket. You have to put *MORE
+// THAN 11* fruits in the basket. Three types of fruits - Apple (4),
+// Mango (2) and Lichi (5) are already given in the basket. You are
+// not allowed to insert any more of these fruits!
+//
+// Make me pass the tests!
+//
+// Execute the command `rustlings hint collections4` if you need
+// hints.
+
+// I AM NOT DONE
+
+use std::collections::HashMap;
+
+#[derive(Hash, PartialEq, Eq)]
+enum Fruit {
+    Apple,
+    Banana,
+    Mango,
+    Lichi,
+    Pineapple,
+}
+
+fn fruit_basket(basket: &mut HashMap<Fruit, u32>) {
+    let fruit_kinds = vec![
+        Fruit::Apple,
+        Fruit::Banana,
+        Fruit::Mango,
+        Fruit::Lichi,
+        Fruit::Pineapple,
+    ];
+
+    for fruit in fruit_kinds {
+        // TODO: Put new fruits if not already present. Note that you
+        // are not allowed to put any type of fruit that's already
+        // present!
+    }
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+
+    fn get_fruit_basket() -> HashMap<Fruit, u32> {
+        let mut basket = HashMap::<Fruit, u32>::new();
+        basket.insert(Fruit::Apple, 4);
+        basket.insert(Fruit::Mango, 2);
+        basket.insert(Fruit::Lichi, 5);
+
+        basket
+    }
+
+    #[test]
+    fn test_given_fruits_are_not_modified() {
+        let mut basket = get_fruit_basket();
+        fruit_basket(&mut basket);
+        assert_eq!(*basket.get(&Fruit::Apple).unwrap(), 4);
+        assert_eq!(*basket.get(&Fruit::Mango).unwrap(), 2);
+        assert_eq!(*basket.get(&Fruit::Lichi).unwrap(), 5);
+    }
+
+    #[test]
+    fn at_least_five_types_of_fruits() {
+        let mut basket = get_fruit_basket();
+        fruit_basket(&mut basket);
+        let count_fruit_kinds = basket.len();
+        assert!(count_fruit_kinds == 5);
+    }
+
+    #[test]
+    fn greater_than_eleven_fruits() {
+        let mut basket = get_fruit_basket();
+        fruit_basket(&mut basket);
+        let count = basket
+            .values()
+            .sum::<u32>();
+        assert!(count > 11);
+    }
+}

exercises/collections/vec1.rs

@@ -0,0 +1,25 @@
+// vec1.rs
+// Your task is to create a `Vec` which holds the exact same elements
+// as in the array `a`.
+// Make me compile and pass the test!
+// Execute the command `rustlings hint collections1` if you need hints.
+
+// I AM NOT DONE
+
+fn array_and_vec() -> ([i32; 4], Vec<i32>) {
+    let a = [10, 20, 30, 40]; // a plain array
+    let v = // TODO: declare your vector here with the macro for vectors
+
+    (a, v)
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+
+    #[test]
+    fn test_array_and_vec_similarity() {
+        let (a, v) = array_and_vec();
+        assert!(a.iter().zip(v.iter()).all(|(x, y)| x == y));
+    }
+}

exercises/collections/vec2.rs

@@ -0,0 +1,38 @@
+// vec2.rs
+// A Vec of even numbers is given. Your task is to complete the loop
+// so that each number in the Vec is multiplied by 2.
+//
+// Make me pass the test!
+//
+// Execute the command `rustlings hint collections2` if you need
+// hints.
+
+// I AM NOT DONE
+
+fn vec_loop(mut v: Vec<i32>) -> Vec<i32> {
+    for i in v.iter_mut() {
+        // TODO: Fill this up so that each element in the Vec `v` is
+        // multiplied by 2.
+    }
+
+    // At this point, `v` should be equal to [4, 8, 12, 16, 20].
+    v
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+
+    #[test]
+    fn test_vec_loop() {
+        let v: Vec<i32> = (1..).filter(|x| x % 2 == 0).take(5).collect();
+        let ans = vec_loop(v.clone());
+
+        assert_eq!(
+            ans,
+            v.iter()
+                .map(|x| x * 2)
+                .collect::<Vec<i32>>()
+        );
+    }
+}

exercises/conversions/README.md

@@ -0,0 +1,20 @@
+### Type conversions
+
+
+Rust offers a multitude of ways to convert a value of a given type into another type.
+
+The simplest form of type conversion is a type cast expression. It is denoted with the binary operator `as`. For instance, `println!("{}", 1 + 1.0);` would not compile, since `1` is an integer while `1.0` is a float. However, `println!("{}", 1 as f32 + 1.0)` should compile. The exercise [`using_as`](using_as.rs) tries to cover this.
+
+Rust also offers traits that facilitate type conversions upon implementation. These traits can be found under the [`convert`](https://doc.rust-lang.org/std/convert/index.html) module.
+The traits are the following:
+- `From` and `Into` covered in [`from_into`](from_into.rs)
+- `TryFrom` and `TryInto` covered in [`try_from_into`](try_from_into.rs)
+- `AsRef` and `AsMut` covered in [`as_ref_mut`](as_ref_mut.rs)
+
+Furthermore, the `std::str` module offers a trait called [`FromStr`](https://doc.rust-lang.org/std/str/trait.FromStr.html) which helps with converting strings into target types via the `parse` method on strings. If properly implemented for a given type `Person`, then `let p: Person = "Mark,20".parse().unwrap()` should both compile and run without panicking.
+
+These should be the main ways ***within the standard library*** to convert data into your desired types.
+
+#### Book Sections
+
+These are not directly covered in the book, but the standard library has great documentation for [conversions here](https://doc.rust-lang.org/std/convert/index.html). The `FromStr` trait is also covered [here](https://doc.rust-lang.org/std/str/trait.FromStr.html).

exercises/conversions/as_ref_mut.rs

@@ -0,0 +1,52 @@
+// AsRef and AsMut allow for cheap reference-to-reference conversions.
+// Read more about them at https://doc.rust-lang.org/std/convert/trait.AsRef.html
+// and https://doc.rust-lang.org/std/convert/trait.AsMut.html, respectively.
+
+// I AM NOT DONE
+
+// Obtain the number of bytes (not characters) in the given argument
+// Add the AsRef trait appropriately as a trait bound
+fn byte_counter<T>(arg: T) -> usize {
+    arg.as_ref().as_bytes().len()
+}
+
+// Obtain the number of characters (not bytes) in the given argument
+// Add the AsRef trait appropriately as a trait bound
+fn char_counter<T>(arg: T) -> usize {
+    arg.as_ref().chars().count()
+}
+
+fn main() {
+    let s = "Café au lait";
+    println!("{}", char_counter(s));
+    println!("{}", byte_counter(s));
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+
+    #[test]
+    fn different_counts() {
+        let s = "Café au lait";
+        assert_ne!(char_counter(s), byte_counter(s));
+    }
+
+    #[test]
+    fn same_counts() {
+        let s = "Cafe au lait";
+        assert_eq!(char_counter(s), byte_counter(s));
+    }
+
+    #[test]
+    fn different_counts_using_string() {
+        let s = String::from("Café au lait");
+        assert_ne!(char_counter(s.clone()), byte_counter(s));
+    }
+
+    #[test]
+    fn same_counts_using_string() {
+        let s = String::from("Cafe au lait");
+        assert_eq!(char_counter(s.clone()), byte_counter(s));
+    }
+}

exercises/conversions/from_into.rs

@@ -0,0 +1,118 @@
+// The From trait is used for value-to-value conversions.
+// If From is implemented correctly for a type, the Into trait should work conversely.
+// You can read more about it at https://doc.rust-lang.org/std/convert/trait.From.html
+#[derive(Debug)]
+struct Person {
+    name: String,
+    age: usize,
+}
+
+// We implement the Default trait to use it as a fallback
+// when the provided string is not convertible into a Person object
+impl Default for Person {
+    fn default() -> Person {
+        Person {
+            name: String::from("John"),
+            age: 30,
+        }
+    }
+}
+
+// Your task is to complete this implementation
+// in order for the line `let p = Person::from("Mark,20")` to compile
+// Please note that you'll need to parse the age component into a `usize`
+// with something like `"4".parse::<usize>()`. The outcome of this needs to
+// be handled appropriately.
+//
+// Steps:
+// 1. If the length of the provided string is 0, then return the default of Person
+// 2. Split the given string on the commas present in it
+// 3. Extract the first element from the split operation and use it as the name
+// 4. If the name is empty, then return the default of Person
+// 5. Extract the other element from the split operation and parse it into a `usize` as the age
+// If while parsing the age, something goes wrong, then return the default of Person
+// Otherwise, then return an instantiated Person object with the results
+
+// I AM NOT DONE
+
+impl From<&str> for Person {
+    fn from(s: &str) -> Person {
+    }
+}
+
+fn main() {
+    // Use the `from` function
+    let p1 = Person::from("Mark,20");
+    // Since From is implemented for Person, we should be able to use Into
+    let p2: Person = "Gerald,70".into();
+    println!("{:?}", p1);
+    println!("{:?}", p2);
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+    #[test]
+    fn test_default() {
+        // Test that the default person is 30 year old John
+        let dp = Person::default();
+        assert_eq!(dp.name, "John");
+        assert_eq!(dp.age, 30);
+    }
+    #[test]
+    fn test_bad_convert() {
+        // Test that John is returned when bad string is provided
+        let p = Person::from("");
+        assert_eq!(p.name, "John");
+        assert_eq!(p.age, 30);
+    }
+    #[test]
+    fn test_good_convert() {
+        // Test that "Mark,20" works
+        let p = Person::from("Mark,20");
+        assert_eq!(p.name, "Mark");
+        assert_eq!(p.age, 20);
+    }
+    #[test]
+    fn test_bad_age() {
+        // Test that "Mark,twenty" will return the default person due to an error in parsing age
+        let p = Person::from("Mark,twenty");
+        assert_eq!(p.name, "John");
+        assert_eq!(p.age, 30);
+    }
+
+    #[test]
+    fn test_missing_comma_and_age() {
+        let p: Person = Person::from("Mark");
+        assert_eq!(p.name, "John");
+        assert_eq!(p.age, 30);
+    }
+
+    #[test]
+    fn test_missing_age() {
+        let p: Person = Person::from("Mark,");
+        assert_eq!(p.name, "John");
+        assert_eq!(p.age, 30);
+    }
+
+    #[test]
+    fn test_missing_name() {
+        let p: Person = Person::from(",1");
+        assert_eq!(p.name, "John");
+        assert_eq!(p.age, 30);
+    }
+
+    #[test]
+    fn test_missing_name_and_age() {
+        let p: Person = Person::from(",");
+        assert_eq!(p.name, "John");
+        assert_eq!(p.age, 30);
+    }
+
+    #[test]
+    fn test_missing_name_and_invalid_age() {
+        let p: Person = Person::from(",one");
+        assert_eq!(p.name, "John");
+        assert_eq!(p.age, 30);
+    }
+}

exercises/conversions/from_str.rs

@@ -0,0 +1,85 @@
+// This does practically the same thing that TryFrom<&str> does.
+// Additionally, upon implementing FromStr, you can use the `parse` method
+// on strings to generate an object of the implementor type.
+// You can read more about it at https://doc.rust-lang.org/std/str/trait.FromStr.html
+use std::str::FromStr;
+
+#[derive(Debug)]
+struct Person {
+    name: String,
+    age: usize,
+}
+
+// I AM NOT DONE
+// Steps:
+// 1. If the length of the provided string is 0, then return an error
+// 2. Split the given string on the commas present in it
+// 3. Extract the first element from the split operation and use it as the name
+// 4. If the name is empty, then return an error
+// 5. Extract the other element from the split operation and parse it into a `usize` as the age
+//    with something like `"4".parse::<usize>()`.
+// If while parsing the age, something goes wrong, then return an error
+// Otherwise, then return a Result of a Person object
+impl FromStr for Person {
+    type Err = String;
+    fn from_str(s: &str) -> Result<Person, Self::Err> {
+    }
+}
+
+fn main() {
+    let p = "Mark,20".parse::<Person>().unwrap();
+    println!("{:?}", p);
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+
+    #[test]
+    fn empty_input() {
+        assert!("".parse::<Person>().is_err());
+    }
+    #[test]
+    fn good_input() {
+        let p = "John,32".parse::<Person>();
+        assert!(p.is_ok());
+        let p = p.unwrap();
+        assert_eq!(p.name, "John");
+        assert_eq!(p.age, 32);
+    }
+    #[test]
+    #[should_panic]
+    fn missing_age() {
+        "John,".parse::<Person>().unwrap();
+    }
+
+    #[test]
+    #[should_panic]
+    fn invalid_age() {
+        "John,twenty".parse::<Person>().unwrap();
+    }
+
+    #[test]
+    #[should_panic]
+    fn missing_comma_and_age() {
+        "John".parse::<Person>().unwrap();
+    }
+
+    #[test]
+    #[should_panic]
+    fn missing_name() {
+        ",1".parse::<Person>().unwrap();
+    }
+
+    #[test]
+    #[should_panic]
+    fn missing_name_and_age() {
+        ",".parse::<Person>().unwrap();
+    }
+
+    #[test]
+    #[should_panic]
+    fn missing_name_and_invalid_age() {
+        ",one".parse::<Person>().unwrap();
+    }
+}

exercises/conversions/try_from_into.rs

@@ -0,0 +1,155 @@
+// TryFrom is a simple and safe type conversion that may fail in a controlled way under some circumstances.
+// Basically, this is the same as From. The main difference is that this should return a Result type
+// instead of the target type itself.
+// You can read more about it at https://doc.rust-lang.org/std/convert/trait.TryFrom.html
+use std::convert::{TryFrom, TryInto};
+
+#[derive(Debug, PartialEq)]
+struct Color {
+    red: u8,
+    green: u8,
+    blue: u8,
+}
+
+// I AM NOT DONE
+
+// Your task is to complete this implementation
+// and return an Ok result of inner type Color.
+// You need create implementation for a tuple of three integer,
+// an array of three integer and slice of integer.
+//
+// Note, that implementation for tuple and array will be checked at compile-time,
+// but slice implementation need check slice length!
+// Also note, that chunk of correct rgb color must be integer in range 0..=255.
+
+// Tuple implementation
+impl TryFrom<(i16, i16, i16)> for Color {
+    type Error = String;
+    fn try_from(tuple: (i16, i16, i16)) -> Result<Self, Self::Error> {}
+}
+
+// Array implementation
+impl TryFrom<[i16; 3]> for Color {
+    type Error = String;
+    fn try_from(arr: [i16; 3]) -> Result<Self, Self::Error> {}
+}
+
+// Slice implementation
+impl TryFrom<&[i16]> for Color {
+    type Error = String;
+    fn try_from(slice: &[i16]) -> Result<Self, Self::Error> {}
+}
+
+fn main() {
+    // Use the `from` function
+    let c1 = Color::try_from((183, 65, 14));
+    println!("{:?}", c1);
+
+    // Since From is implemented for Color, we should be able to use Into
+    let c2: Result<Color, _> = [183, 65, 14].try_into();
+    println!("{:?}", c2);
+
+    let v = vec![183, 65, 14];
+    // With slice we should use `from` function
+    let c3 = Color::try_from(&v[..]);
+    println!("{:?}", c3);
+    // or take slice within round brackets and use Into
+    let c4: Result<Color, _> = (&v[..]).try_into();
+    println!("{:?}", c4);
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+
+    #[test]
+    fn test_tuple_out_of_range_positive() {
+        assert!(Color::try_from((256, 1000, 10000)).is_err());
+    }
+    #[test]
+    fn test_tuple_out_of_range_negative() {
+        assert!(Color::try_from((-1, -10, -256)).is_err());
+    }
+    #[test]
+    fn test_tuple_sum() {
+        assert!(Color::try_from((-1, 255, 255)).is_err());
+    }
+    #[test]
+    fn test_tuple_correct() {
+        let c: Result<Color, String> = (183, 65, 14).try_into();
+        assert_eq!(
+            c,
+            Ok(Color {
+                red: 183,
+                green: 65,
+                blue: 14
+            })
+        );
+    }
+    #[test]
+    fn test_array_out_of_range_positive() {
+        let c: Color = [1000, 10000, 256].try_into();
+        assert!(c.is_err());
+    }
+    #[test]
+    fn test_array_out_of_range_negative() {
+        let c: Color = [-10, -256, -1].try_into();
+        assert!(c.is_err());
+    }
+    #[test]
+    fn test_array_sum() {
+        let c: Color = [-1, 255, 255].try_into();
+        assert!(c.is_err());
+    }
+    #[test]
+    #[test]
+    fn test_array_correct() {
+        let c: Result<Color, String> = [183, 65, 14].try_into();
+        assert_eq!(
+            c,
+            Ok(Color {
+                red: 183,
+                green: 65,
+                blue: 14
+            })
+        );
+    }
+    #[test]
+    fn test_slice_out_of_range_positive() {
+        let arr = [10000, 256, 1000];
+        assert!(Color::try_from(&arr[..]).is_err());
+    }
+    #[test]
+    fn test_slice_out_of_range_negative() {
+        let arr = [-256, -1, -10];
+        assert!(Color::try_from(&arr[..]).is_err());
+    }
+    #[test]
+    fn test_slice_sum() {
+        let arr = [-1, 255, 255];
+        assert!(Color::try_from(&arr[..]).is_err());
+    }
+    #[test]
+    fn test_slice_correct() {
+        let v = vec![183, 65, 14];
+        let c: Result<Color, String> = Color::try_from(&v[..]);
+        assert_eq!(
+            c,
+            Ok(Color {
+                red: 183,
+                green: 65,
+                blue: 14
+            })
+        );
+    }
+    #[test]
+    fn test_slice_excess_length() {
+        let v = vec![0, 0, 0, 0];
+        assert!(Color::try_from(&v[..]).is_err());
+    }
+    #[test]
+    fn test_slice_insufficient_length() {
+        let v = vec![0, 0];
+        assert!(Color::try_from(&v[..]).is_err());
+    }
+}

exercises/conversions/using_as.rs

@@ -0,0 +1,28 @@
+// Type casting in Rust is done via the usage of the `as` operator.
+// Please note that the `as` operator is not only used when type casting.
+// It also helps with renaming imports.
+//
+// The goal is to make sure that the division does not fail to compile
+// and returns the proper type.
+
+// I AM NOT DONE
+
+fn average(values: &[f64]) -> f64 {
+    let total = values.iter().fold(0.0, |a, b| a + b);
+    total / values.len()
+}
+
+fn main() {
+    let values = [3.5, 0.3, 13.0, 11.7];
+    println!("{}", average(&values));
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+
+    #[test]
+    fn returns_proper_type_and_value() {
+        assert_eq!(average(&[3.5, 0.3, 13.0, 11.7]), 7.125);
+    }
+}

exercises/enums/README.md

@@ -1,7 +1,10 @@
 ### Enums
 
-Rust allows you to define a type called `enums` which allow you to enumerate possible values. In combination with enums, we have the concept of `pattern matching` in Rust, which makes it easy to run different code for different values of an enumeration. Enums, while available in many languages, Rust's enums are most similar to `algebraic data types` in functional languages, such as F#, OCaml, and Haskell.
+Rust allows you to define types called "enums" which enumerate possible values.
+Enums are a feature in many languages, but their capabilities differ in each language. Rust’s enums are most similar to algebraic data types in functional languages, such as F#, OCaml, and Haskell.
+Useful in combination with enums is Rust's "pattern matching" facility, which makes it easy to run different code for different values of an enumeration.
 
 #### Book Sections
 
 - [Enums](https://doc.rust-lang.org/book/ch06-00-enums.html)
+- [Pattern syntax](https://doc.rust-lang.org/book/ch18-03-pattern-syntax.html)

exercises/enums/enums1.rs

@@ -1,5 +1,7 @@
 // enums1.rs
-// Make me compile! Scroll down for hints!
+// Make me compile! Execute `rustlings hint enums1` for hints!
+
+// I AM NOT DONE
 
 #[derive(Debug)]
 enum Message {
@@ -12,31 +14,3 @@ fn main() {
     println!("{:?}", Message::Move);
     println!("{:?}", Message::ChangeColor);
 }
-
-
-
-
-
-
-
-
-
-
-
-
-
-
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-
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-
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-
-
-
-// Hint: The declaration of the enumeration type has not been defined yet.

exercises/enums/enums2.rs

@@ -1,5 +1,7 @@
 // enums2.rs
-// Make me compile! Scroll down for hints
+// Make me compile! Execute `rustlings hint enums2` for hints!
+
+// I AM NOT DONE
 
 #[derive(Debug)]
 enum Message {
@@ -14,48 +16,13 @@ impl Message {
 
 fn main() {
     let messages = [
-        Message::Move{ x: 10, y: 30 },
+        Message::Move { x: 10, y: 30 },
         Message::Echo(String::from("hello world")),
         Message::ChangeColor(200, 255, 255),
-        Message::Quit
+        Message::Quit,
     ];
 
     for message in &messages {
         message.call();
     }
 }
-
-
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-
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-
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-
-
-
-// Hint: you can create enumerations that have different variants with different types
-// such as no data, anonymous structs, a single string, tuples, ...etc

exercises/enums/enums3.rs

@@ -1,19 +1,21 @@
 // enums3.rs
 // Address all the TODOs to make the tests pass!
 
+// I AM NOT DONE
+
 enum Message {
     // TODO: implement the message variant types based on their usage below
 }
 
 struct Point {
     x: u8,
-    y: u8
+    y: u8,
 }
 
 struct State {
     color: (u8, u8, u8),
     position: Point,
-    quit: bool
+    quit: bool,
 }
 
 impl State {
@@ -44,14 +46,14 @@ mod tests {
 
     #[test]
     fn test_match_message_call() {
-        let mut state = State{
+        let mut state = State {
             quit: false,
-            position: Point{ x: 0, y: 0 },
-            color: (0, 0, 0)
+            position: Point { x: 0, y: 0 },
+            color: (0, 0, 0),
         };
-        state.process(Message::ChangeColor(255, 0, 255));
+        state.process(Message::ChangeColor((255, 0, 255)));
         state.process(Message::Echo(String::from("hello world")));
-        state.process(Message::Move{ x: 10, y: 15 });
+        state.process(Message::Move(Point { x: 10, y: 15 }));
         state.process(Message::Quit);
 
         assert_eq!(state.color, (255, 0, 255));
@@ -59,5 +61,4 @@ mod tests {
         assert_eq!(state.position.y, 15);
         assert_eq!(state.quit, true);
     }
-
 }

exercises/error_handling/README.md

@@ -1,5 +1,5 @@
 For this exercise check out the sections:
-- [Error Handling](https://doc.rust-lang.org/book/ch09-02-recoverable-errors-with-result.html) 
-- [Generics](https://doc.rust-lang.org/book/ch10-01-syntax.html) 
+- [Error Handling](https://doc.rust-lang.org/book/ch09-02-recoverable-errors-with-result.html)
+- [Generics](https://doc.rust-lang.org/book/ch10-01-syntax.html)
 
 of the Rust Book.

exercises/error_handling/errors1.rs

@@ -4,7 +4,9 @@
 // was, instead of just sometimes returning `None`. The 2nd test currently
 // does not compile or pass, but it illustrates the behavior we would like
 // this function to have.
-// Scroll down for hints!!!
+// Execute `rustlings hint errors1` for hints!
+
+// I AM NOT DONE
 
 pub fn generate_nametag_text(name: String) -> Option<String> {
     if name.len() > 0 {
@@ -38,36 +40,3 @@ mod tests {
         );
     }
 }
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-// `Err` is one of the variants of `Result`, so what the 2nd test is saying
-// is that `generate_nametag_text` should return a `Result` instead of an
-// `Option`.
-
-// To make this change, you'll need to:
-// - update the return type in the function signature to be a Result<String, String> that
-//   could be the variants `Ok(String)` and `Err(String)`
-// - change the body of the function to return `Ok(stuff)` where it currently
-//   returns `Some(stuff)`
-// - change the body of the function to return `Err(error message)` where it
-//   currently returns `None`
-// - change the first test to expect `Ok(stuff)` where it currently expects
-//   `Some(stuff)`.

exercises/error_handling/errors2.rs

@@ -14,7 +14,9 @@
 // and add.
 
 // There are at least two ways to implement this that are both correct-- but
-// one is a lot shorter! Scroll down for hints to both ways.
+// one is a lot shorter! Execute `rustlings hint errors2` for hints to both ways.
+
+// I AM NOT DONE
 
 use std::num::ParseIntError;
 
@@ -43,27 +45,3 @@ mod tests {
         );
     }
 }
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-// One way to handle this is using a `match` statement on
-// `item_quantity.parse::<i32>()` where the cases are `Ok(something)` and
-// `Err(something)`. This pattern is very common in Rust, though, so there's
-// a `?` operator that does pretty much what you would make that match statement
-// do for you! Take a look at this section of the Error Handling chapter:
-// https://doc.rust-lang.org/book/ch09-02-recoverable-errors-with-result.html#a-shortcut-for-propagating-errors-the--operator
-// and give it a try!

exercises/error_handling/errors3.rs

@@ -1,7 +1,10 @@
 // errors3.rs
 // This is a program that is trying to use a completed version of the
 // `total_cost` function from the previous exercise. It's not working though!
-// Why not? What should we do to fix it? Scroll for hints!
+// Why not? What should we do to fix it?
+// Execute `rustlings hint errors3` for hints!
+
+// I AM NOT DONE
 
 use std::num::ParseIntError;
 
@@ -26,22 +29,3 @@ pub fn total_cost(item_quantity: &str) -> Result<i32, ParseIntError> {
 
     Ok(qty * cost_per_item + processing_fee)
 }
-
-
-
-
-
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-
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-
-
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-
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-
-
-// If other functions can return a `Result`, why shouldn't `main`?

exercises/error_handling/errorsn.rs

@@ -2,8 +2,10 @@
 // This is a bigger error exercise than the previous ones!
 // You can do it! :)
 //
-// Edit the `read_and_validate` function so that it compiles and
-// passes the tests... so many things could go wrong!
+// Edit the `read_and_validate` function ONLY. Don't create any Errors
+// that do not already exist.
+//
+// So many things could go wrong!
 //
 // - Reading from stdin could produce an io::Error
 // - Parsing the input could produce a num::ParseIntError
@@ -13,7 +15,9 @@
 // type goes where the question marks are, and how do we return
 // that type from the body of read_and_validate?
 //
-// Scroll down for hints :)
+// Execute `rustlings hint errorsn` for hints :)
+
+// I AM NOT DONE
 
 use std::error;
 use std::fmt;
@@ -28,6 +32,10 @@ fn read_and_validate(b: &mut dyn io::BufRead) -> Result<PositiveNonzeroInteger,
     answer
 }
 
+//
+// Nothing below this needs to be modified
+//
+
 // This is a test helper function that turns a &str into a BufReader.
 fn test_with_str(s: &str) -> Result<PositiveNonzeroInteger, Box<dyn error::Error>> {
     let mut b = io::BufReader::new(s.as_bytes());
@@ -98,150 +106,12 @@ enum CreationError {
 
 impl fmt::Display for CreationError {
     fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
-        f.write_str((self as &dyn error::Error).description())
+        let description = match *self {
+            CreationError::Negative => "Number is negative",
+            CreationError::Zero => "Number is zero",
+        };
+        f.write_str(description)
     }
 }
 
-impl error::Error for CreationError {
-    fn description(&self) -> &str {
-        match *self {
-            CreationError::Negative => "Negative",
-            CreationError::Zero => "Zero",
-        }
-    }
-}
-
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-
-// First hint: To figure out what type should go where the ??? is, take a look
-// at the test helper function `test_with_str`, since it returns whatever
-// `read_and_validate` returns and`test_with_str` has its signature fully
-// specified.
-
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-
-
-// Next hint: There are three places in `read_and_validate` that we call a
-// function that returns a `Result` (that is, the functions might fail).
-// Apply the `?` operator on those calls so that we return immediately from
-// `read_and_validate` if those function calls fail.
-
-
-
-
-
-
-
-
-
-
-
-
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-
-
-
-
-
-// Another hint: under the hood, the `?` operator calls `From::from`
-// on the error value to convert it to a boxed trait object, a Box<dyn error::Error>,
-// which is polymorphic-- that means that lots of different kinds of errors
-// can be returned from the same function because all errors act the same
-// since they all implement the `error::Error` trait.
-// Check out this section of the book:
-// https://doc.rust-lang.org/book/ch09-02-recoverable-errors-with-result.html#a-shortcut-for-propagating-errors-the--operator
-
-
-
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-
-
-
-
-
-
-// Another another hint: Note that because the `?` operator returns
-// the *unwrapped* value in the `Ok` case, if we want to return a `Result` from
-// `read_and_validate` for *its* success case, we'll have to rewrap a value
-// that we got from the return value of a `?`ed call in an `Ok`-- this will
-// look like `Ok(something)`.
-
-
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-
-// Another another another hint: `Result`s must be "used", that is, you'll
-// get a warning if you don't handle a `Result` that you get in your
-// function. Read more about that in the `std::result` module docs:
-// https://doc.rust-lang.org/std/result/#results-must-be-used
+impl error::Error for CreationError {}

exercises/error_handling/option1.rs

@@ -1,57 +0,0 @@
-// option1.rs
-// This example panics because the second time it calls `pop`, the `vec`
-// is empty, so `pop` returns `None`, and `unwrap` panics if it's called
-// on `None`. Handle this in a more graceful way than calling `unwrap`!
-// Scroll down for hints :)
-
-pub fn pop_too_much() -> bool {
-    let mut list = vec![3];
-
-    let last = list.pop().unwrap();
-    println!("The last item in the list is {:?}", last);
-
-    let second_to_last = list.pop().unwrap();
-    println!(
-        "The second-to-last item in the list is {:?}",
-        second_to_last
-    );
-    true
-}
-
-#[cfg(test)]
-mod tests {
-    use super::*;
-
-    #[test]
-    fn should_not_panic() {
-        assert!(pop_too_much());
-    }
-}
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
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-
-
-
-
-
-
-// Try using a `match` statement where the arms are `Some(thing)` and `None`.
-// Or set a default value to print out if you get `None` by using the
-// function `unwrap_or`.
-// Or use an `if let` statement on the result of `pop()` to both destructure
-// a `Some` value and only print out something if we have a value!

exercises/error_handling/result1.rs

@@ -1,5 +1,7 @@
 // result1.rs
-// Make this test pass! Scroll down for hints :)
+// Make this test pass! Execute `rustlings hint result1` for hints :)
+
+// I AM NOT DONE
 
 #[derive(PartialEq, Debug)]
 struct PositiveNonzeroInteger(u64);
@@ -25,22 +27,3 @@ fn test_creation() {
     );
     assert_eq!(Err(CreationError::Zero), PositiveNonzeroInteger::new(0));
 }
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-// `PositiveNonzeroInteger::new` is always creating a new instance and returning an `Ok` result.
-// It should be doing some checking, returning an `Err` result if those checks fail, and only
-// returning an `Ok` result if those checks determine that everything is... okay :)

exercises/functions/functions1.rs

@@ -1,44 +1,8 @@
 // functions1.rs
-// Make me compile! Scroll down for hints :)
+// Make me compile! Execute `rustlings hint functions1` for hints :)
+
+// I AM NOT DONE
 
 fn main() {
     call_me();
 }
-
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-// This main function is calling a function that it expects to exist, but the
-// function doesn't exist. It expects this function to have the name `call_me`.
-// It expects this function to not take any arguments and not return a value.
-// Sounds a lot like `main`, doesn't it?

exercises/functions/functions2.rs

@@ -1,5 +1,7 @@
 // functions2.rs
-// Make me compile! Scroll down for hints :)
+// Make me compile! Execute `rustlings hint functions2` for hints :)
+
+// I AM NOT DONE
 
 fn main() {
     call_me(3);
@@ -10,33 +12,3 @@ fn call_me(num) {
         println!("Ring! Call number {}", i + 1);
     }
 }
-
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-
-
-// Rust requires that all parts of a function's signature have type annotations,
-// but `call_me` is missing the type annotation of `num`.

exercises/functions/functions3.rs

@@ -1,5 +1,7 @@
 // functions3.rs
-// Make me compile! Scroll down for hints :)
+// Make me compile! Execute `rustlings hint functions3` for hints :)
+
+// I AM NOT DONE
 
 fn main() {
     call_me();
@@ -10,33 +12,3 @@ fn call_me(num: i32) {
         println!("Ring! Call number {}", i + 1);
     }
 }
-
-
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-
-
-// This time, the function *declaration* is okay, but there's something wrong
-// with the place where we're calling the function.

exercises/functions/functions4.rs

@@ -1,8 +1,10 @@
 // functions4.rs
-// Make me compile! Scroll down for hints :)
+// Make me compile! Execute `rustlings hint functions4` for hints :)
 
 // This store is having a sale where if the price is an even number, you get
-// 10 (money unit) off, but if it's an odd number, it's 3 (money unit) less.
+// 10 Rustbucks off, but if it's an odd number, it's 3 Rustbucks off.
+
+// I AM NOT DONE
 
 fn main() {
     let original_price = 51;
@@ -20,25 +22,3 @@ fn sale_price(price: i32) -> {
 fn is_even(num: i32) -> bool {
     num % 2 == 0
 }
-
-
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-
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-
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-
-
-
-
-// The error message points to line 12 and says it expects a type after the
-// `->`. This is where the function's return type should be-- take a look at
-// the `is_even` function for an example!

exercises/functions/functions5.rs

@@ -1,5 +1,7 @@
 // functions5.rs
-// Make me compile! Scroll down for hints :)
+// Make me compile! Execute `rustlings hint functions5` for hints :)
+
+// I AM NOT DONE
 
 fn main() {
     let answer = square(3);
@@ -9,39 +11,3 @@ fn main() {
 fn square(num: i32) -> i32 {
     num * num;
 }
-
-
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-
-
-// This is a really common error that can be fixed by removing one character.
-// It happens because Rust distinguishes between expressions and statements: expressions return
-// a value based on its operand, and statements simply return a () type which behaves just like `void` in C/C++ language.
-// We want to return a value of `i32` type from the `square` function, but it is returning a `()` type...
-// They are not the same. There are two solutions:
-// 1. Add a `return` ahead of `num * num;`
-// 2. remove `;`, make it to be `num * num`

exercises/generics/README.md

@@ -0,0 +1,7 @@
+### Generics
+
+In this section you'll learn about saving yourself many lines of code with generics!
+
+### Book Sections
+
+- [Generic Data Types](https://doc.rust-lang.org/stable/book/ch10-01-syntax.html)

exercises/generics/generics1.rs

@@ -0,0 +1,9 @@
+// This shopping list program isn't compiling!
+// Use your knowledge of generics to fix it.
+
+// I AM NOT DONE
+
+fn main() {
+    let mut shopping_list: Vec<?> = Vec::new();
+    shopping_list.push("milk");
+}

exercises/generics/generics2.rs

@@ -0,0 +1,29 @@
+// This powerful wrapper provides the ability to store a positive integer value.
+// Rewrite it using generics so that it supports wrapping ANY type.
+
+// I AM NOT DONE
+
+struct Wrapper {
+    value: u32,
+}
+
+impl Wrapper {
+    pub fn new(value: u32) -> Self {
+        Wrapper { value }
+    }
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+
+    #[test]
+    fn store_u32_in_wrapper() {
+        assert_eq!(Wrapper::new(42).value, 42);
+    }
+
+    #[test]
+    fn store_str_in_wrapper() {
+        assert_eq!(Wrapper::new("Foo").value, "Foo");
+    }
+}

exercises/generics/generics3.rs

@@ -0,0 +1,58 @@
+// An imaginary magical school has a new report card generation system written in Rust!
+// Currently the system only supports creating report cards where the student's grade
+// is represented numerically (e.g. 1.0 -> 5.5).
+// However, the school also issues alphabetical grades (A+ -> F-) and needs
+// to be able to print both types of report card!
+
+// Make the necessary code changes in the struct ReportCard and the impl block
+// to support alphabetical report cards. Change the Grade in the second test to "A+"
+// to show that your changes allow alphabetical grades.
+
+// Execute 'rustlings hint generics3' for hints!
+
+// I AM NOT DONE
+
+pub struct ReportCard {
+    pub grade: f32,
+    pub student_name: String,
+    pub student_age: u8,
+}
+
+impl ReportCard {
+    pub fn print(&self) -> String {
+        format!("{} ({}) - achieved a grade of {}",
+            &self.student_name, &self.student_age, &self.grade)
+    }
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+
+    #[test]
+    fn generate_numeric_report_card() {
+        let report_card = ReportCard {
+            grade: 2.1,
+            student_name: "Tom Wriggle".to_string(),
+            student_age: 12,
+        };
+        assert_eq!(
+            report_card.print(),
+            "Tom Wriggle (12) - achieved a grade of 2.1"
+        );
+    }
+
+    #[test]
+    fn generate_alphabetic_report_card() {
+        // TODO: Make sure to change the grade here after you finish the exercise.
+        let report_card = ReportCard {
+            grade: 2.1,
+            student_name: "Gary Plotter".to_string(),
+            student_age: 11,
+        };
+        assert_eq!(
+            report_card.print(),
+            "Gary Plotter (11) - achieved a grade of A+"
+        );
+    }
+}

exercises/if/if1.rs

@@ -1,11 +1,13 @@
 // if1.rs
 
+// I AM NOT DONE
+
 pub fn bigger(a: i32, b: i32) -> i32 {
     // Complete this function to return the bigger number!
     // Do not use:
     // - another function call
     // - additional variables
-    // Scroll down for hints.
+    // Execute `rustlings hint if1` for hints
 }
 
 // Don't mind this for now :)
@@ -23,36 +25,3 @@ mod tests {
         assert_eq!(42, bigger(32, 42));
     }
 }
-
-
-
-
-
-
-
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-
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-
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-
-
-
-
-
-
-
-
-
-
-
-// It's possible to do this in one line if you would like!
-// Some similar examples from other languages:
-// - In C(++) this would be: `a > b ? a : b`
-// - In Python this would be:  `a if a > b else b`
-// Remember in Rust that:
-// - the `if` condition does not need to be surrounded by parentheses
-// - `if`/`else` conditionals are expressions
-// - Each condition is followed by a `{}` block.

exercises/if/if2.rs

@@ -0,0 +1,36 @@
+// if2.rs
+
+// Step 1: Make me compile!
+// Step 2: Get the bar_for_fuzz and default_to_baz tests passing!
+// Execute the command `rustlings hint if2` if you want a hint :)
+
+// I AM NOT DONE
+
+pub fn fizz_if_foo(fizzish: &str) -> &str {
+    if fizzish == "fizz" {
+        "foo"
+    } else {
+        1
+    }
+}
+
+// No test changes needed!
+#[cfg(test)]
+mod tests {
+    use super::*;
+
+    #[test]
+    fn foo_for_fizz() {
+        assert_eq!(fizz_if_foo("fizz"), "foo")
+    }
+
+    #[test]
+    fn bar_for_fuzz() {
+        assert_eq!(fizz_if_foo("fuzz"), "bar")
+    }
+
+    #[test]
+    fn default_to_baz() {
+        assert_eq!(fizz_if_foo("literally anything"), "baz")
+    }
+}

exercises/macros/README.md

@@ -2,7 +2,7 @@
 
 Rust's macro system is very powerful, but also kind of difficult to wrap your
 head around. We're not going to teach you how to write your own fully-featured
-modules, instead we'll show you how to use and create them.
+macros. Instead, we'll show you how to use and create them.
 
 #### Book Sections
 

exercises/macros/macros1.rs

@@ -1,5 +1,7 @@
 // macros1.rs
-// Make me compile! Scroll down for hints :)
+// Make me compile! Execute `rustlings hint macros1` for hints :)
+
+// I AM NOT DONE
 
 macro_rules! my_macro {
     () => {
@@ -10,55 +12,3 @@ macro_rules! my_macro {
 fn main() {
     my_macro();
 }
-
-
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-
-// When you call a macro, you need to add something special compared to a
-// regular function call. If you're stuck, take a look at what's inside
-// `my_macro`.

exercises/macros/macros2.rs

@@ -1,5 +1,7 @@
 // macros2.rs
-// Make me compile! Scroll down for hints :)
+// Make me compile! Execute `rustlings hint macros2` for hints :)
+
+// I AM NOT DONE
 
 fn main() {
     my_macro!();
@@ -10,64 +12,3 @@ macro_rules! my_macro {
         println!("Check out my macro!");
     };
 }
-
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-
-// Macros don't quite play by the same rules as the rest of Rust, in terms of
-// what's available where.
-
-
-
-
-
-
-
-
-// Unlike other things in Rust, the order of "where you define a macro" versus
-// "where you use it" actually matters.

exercises/macros/macros3.rs

@@ -1,5 +1,8 @@
 // macros3.rs
-// Make me compile, without taking the macro out of the module! Scroll down for hints :)
+// Make me compile, without taking the macro out of the module!
+// Execute `rustlings hint macros3` for hints :)
+
+// I AM NOT DONE
 
 mod macros {
     macro_rules! my_macro {
@@ -12,64 +15,3 @@ mod macros {
 fn main() {
     my_macro!();
 }
-
-
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-
-// In order to use a macro outside of its module, you need to do something
-// special to the module to lift the macro out into its parent.
-
-
-
-
-
-
-
-
-// The same trick also works on "extern crate" statements for crates that have
-// exported macros, if you've seen any of those around.

exercises/macros/macros4.rs

@@ -1,5 +1,7 @@
 // macros4.rs
-// Make me compile! Scroll down for hints :)
+// Make me compile! Execute `rustlings hint macros4` for hints :)
+
+// I AM NOT DONE
 
 macro_rules! my_macro {
     () => {
@@ -14,64 +16,3 @@ fn main() {
     my_macro!();
     my_macro!(7777);
 }
-
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-// You only need to add a single character to make this compile.
-
-
-
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-
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-
-
-// The way macros are written, it wants to see something between each
-// "macro arm", so it can separate them.

exercises/modules/modules1.rs

@@ -1,5 +1,7 @@
 // modules1.rs
-// Make me compile! Scroll down for hints :)
+// Make me compile! Execute `rustlings hint modules1` for hints :)
+
+// I AM NOT DONE
 
 mod sausage_factory {
     fn make_sausage() {
@@ -10,34 +12,3 @@ mod sausage_factory {
 fn main() {
     sausage_factory::make_sausage();
 }
-
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-// Everything is private in Rust by default-- but there's a keyword we can use
-// to make something public! The compiler error should point to the thing that
-// needs to be public.

exercises/modules/modules2.rs

@@ -1,5 +1,7 @@
 // modules2.rs
-// Make me compile! Scroll down for hints :)
+// Make me compile! Execute `rustlings hint modules2` for hints :)
+
+// I AM NOT DONE
 
 mod delicious_snacks {
     use self::fruits::PEAR as fruit;
@@ -23,25 +25,3 @@ fn main() {
         delicious_snacks::veggie
     );
 }
-
-
-
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-
-
-
-
-
-
-// The delicious_snacks module is trying to present an external
-// interface (the `fruit` and `veggie` constants) that is different than
-// its internal structure (the `fruits` and `veggies` modules and
-// associated constants). It's almost there except for one keyword missing for
-// each constant.

exercises/move_semantics/move_semantics1.rs

@@ -1,5 +1,7 @@
 // move_semantics1.rs
-// Make me compile! Scroll down for hints :)
+// Make me compile! Execute `rustlings hint move_semantics1` for hints :)
+
+// I AM NOT DONE
 
 fn main() {
     let vec0 = Vec::new();
@@ -22,21 +24,3 @@ fn fill_vec(vec: Vec<i32>) -> Vec<i32> {
 
     vec
 }
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-// So you've got the "cannot borrow immutable local variable `vec1` as mutable" error on line 11,
-// right? The fix for this is going to be adding one keyword, and the addition is NOT on line 11
-// where the error is.

exercises/move_semantics/move_semantics2.rs

@@ -1,5 +1,8 @@
 // move_semantics2.rs
-// Make me compile without changing line 10! Scroll down for hints :)
+// Make me compile without changing line 13!
+// Execute `rustlings hint move_semantics2` for hints :)
+
+// I AM NOT DONE
 
 fn main() {
     let vec0 = Vec::new();
@@ -23,31 +26,3 @@ fn fill_vec(vec: Vec<i32>) -> Vec<i32> {
 
     vec
 }
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-// So `vec0` is being *moved* into the function `fill_vec` when we call it on
-// line 7, which means it gets dropped at the end of `fill_vec`, which means we
-// can't use `vec0` again on line 10 (or anywhere else in `main` after the
-// `fill_vec` call for that matter). We could fix this in a few ways, try them
-// all!
-// 1. Make another, separate version of the data that's in `vec0` and pass that
-// to `fill_vec` instead.
-// 2. Make `fill_vec` borrow its argument instead of taking ownership of it,
-// and then copy the data within the function in order to return an owned
-// `Vec<i32>`
-// 3. Make `fill_vec` *mutably* borrow its argument (which will need to be
-// mutable), modify it directly, then not return anything. Then you can get rid
-// of `vec1` entirely -- note that this will change what gets printed by the
-// first `println!`

exercises/move_semantics/move_semantics3.rs

@@ -1,7 +1,9 @@
 // move_semantics3.rs
 // Make me compile without adding new lines-- just changing existing lines!
 // (no lines with multiple semicolons necessary!)
-// Scroll down for hints :)
+// Execute `rustlings hint move_semantics3` for hints :)
+
+// I AM NOT DONE
 
 fn main() {
     let vec0 = Vec::new();
@@ -22,24 +24,3 @@ fn fill_vec(vec: Vec<i32>) -> Vec<i32> {
 
     vec
 }
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-// The difference between this one and the previous ones is that the first line
-// of `fn fill_vec` that had `let mut vec = vec;` is no longer there. You can,
-// instead of adding that line back, add `mut` in one place that will change
-// an existing binding to be a mutable binding instead of an immutable one :)

exercises/move_semantics/move_semantics4.rs

@@ -1,7 +1,10 @@
 // move_semantics4.rs
 // Refactor this code so that instead of having `vec0` and creating the vector
 // in `fn main`, we instead create it within `fn fill_vec` and transfer the
-// freshly created vector from fill_vec to its caller. Scroll for hints!
+// freshly created vector from fill_vec to its caller.
+// Execute `rustlings hint move_semantics4` for hints!
+
+// I AM NOT DONE
 
 fn main() {
     let vec0 = Vec::new();
@@ -25,24 +28,3 @@ fn fill_vec() -> Vec<i32> {
 
     vec
 }
-
-
-
-
-
-
-
-
-
-
-
-
-// Stop reading whenever you feel like you have enough direction :) Or try
-// doing one step and then fixing the compiler errors that result!
-// So the end goal is to:
-// - get rid of the first line in main that creates the new vector
-// - so then `vec0` doesn't exist, so we can't pass it to `fill_vec`
-// - we don't want to pass anything to `fill_vec`, so its signature should
-//   reflect that it does not take any arguments
-// - since we're not creating a new vec in `main` anymore, we need to create
-//   a new vec in `fill_vec`, similarly to the way we did in `main`

exercises/option/README.md

@@ -0,0 +1,9 @@
+### Option
+
+#### Book Sections
+
+To learn about Option<T>, check out these links:
+
+- [Option Enum Format](https://doc.rust-lang.org/stable/book/ch10-01-syntax.html#in-enum-definitions)
+- [Option Module Documentation](https://doc.rust-lang.org/std/option/)
+- [Option Enum Documentation](https://doc.rust-lang.org/std/option/enum.Option.html)

exercises/option/option1.rs

@@ -0,0 +1,23 @@
+// option1.rs
+// Make me compile! Execute `rustlings hint option1` for hints
+
+// I AM NOT DONE
+
+// you can modify anything EXCEPT for this function's sig
+fn print_number(maybe_number: Option<u16>) {
+    println!("printing: {}", maybe_number.unwrap());
+}
+
+fn main() {
+    print_number(13);
+    print_number(99);
+
+    let mut numbers: [Option<u16>; 5];
+    for iter in 0..5 {
+        let number_to_add: u16 = {
+            ((iter * 1235) + 2) / (4 * 16)
+        };
+
+        numbers[iter as usize] = number_to_add;
+    }
+}

exercises/option/option2.rs

@@ -0,0 +1,25 @@
+// option2.rs
+// Make me compile! Execute `rustlings hint option2` for hints
+
+// I AM NOT DONE
+
+fn main() {
+    let optional_value = Some(String::from("rustlings"));
+    // TODO: Make this an if let statement whose value is "Some" type
+    value = optional_value {
+        println!("the value of optional value is: {}", value);
+    } else {
+        println!("The optional value doesn't contain anything!");
+    }
+
+    let mut optional_values_vec: Vec<Option<i8>> = Vec::new();
+    for x in 1..10 {
+        optional_values_vec.push(Some(x));
+    }
+
+    // TODO: make this a while let statement - remember that vector.pop also adds another layer of Option<T>
+    // You can stack `Option<T>`'s into while let and if let
+    value = optional_values_vec.pop() {
+        println!("current value: {}", value);
+    }
+}

exercises/primitive_types/primitive_types1.rs

@@ -2,6 +2,8 @@
 // Fill in the rest of the line that has code missing!
 // No hints, there's no tricks, just get used to typing these :)
 
+// I AM NOT DONE
+
 fn main() {
     // Booleans (`bool`)
 

exercises/primitive_types/primitive_types2.rs

@@ -2,6 +2,8 @@
 // Fill in the rest of the line that has code missing!
 // No hints, there's no tricks, just get used to typing these :)
 
+// I AM NOT DONE
+
 fn main() {
     // Characters (`char`)
 

exercises/primitive_types/primitive_types3.rs

@@ -1,6 +1,8 @@
 // primitive_types3.rs
-// Create an array with at least 100 elements in it where the ??? is. 
-// Scroll down for hints!
+// Create an array with at least 100 elements in it where the ??? is.
+// Execute `rustlings hint primitive_types3` for hints!
+
+// I AM NOT DONE
 
 fn main() {
     let a = ???
@@ -11,37 +13,3 @@ fn main() {
         println!("Meh, I eat arrays like that for breakfast.");
     }
 }
-
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-
-// There's a shorthand to initialize Arrays with a certain size that does not 
-// require you to type in 100 items (but you certainly can if you want!).
-// For example, you can do:
-// let array = ["Are we there yet?"; 10];
-
-// Bonus: what are some other things you could have that would return true
-// for `a.len() >= 100`?

exercises/primitive_types/primitive_types4.rs

@@ -1,68 +1,14 @@
 // primitive_types4.rs
-// Get a slice out of Array a where the ??? is so that the `if` statement
-// returns true. Scroll down for hints!!
+// Get a slice out of Array a where the ??? is so that the test passes.
+// Execute `rustlings hint primitive_types4` for hints!!
+
+// I AM NOT DONE
 
 #[test]
-fn main() {
+fn slice_out_of_array() {
     let a = [1, 2, 3, 4, 5];
 
     let nice_slice = ???
 
     assert_eq!([2, 3, 4], nice_slice)
 }
-
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-// Take a look at the Understanding Ownership -> Slices -> Other Slices section of the book:
-// https://doc.rust-lang.org/book/ch04-03-slices.html
-// and use the starting and ending indices of the items in the Array
-// that you want to end up in the slice.
-
-// If you're curious why the right hand of the `==` comparison does not
-// have an ampersand for a reference since the left hand side is a
-// reference, take a look at the Deref coercions section of the book:
-// https://doc.rust-lang.org/book/ch15-02-deref.html

exercises/primitive_types/primitive_types5.rs

@@ -1,6 +1,8 @@
 // primitive_types5.rs
 // Destructure the `cat` tuple so that the println will work.
-// Scroll down for hints!
+// Execute `rustlings hint primitive_types5` for hints!
+
+// I AM NOT DONE
 
 fn main() {
     let cat = ("Furry McFurson", 3.5);
@@ -8,38 +10,3 @@ fn main() {
 
     println!("{} is {} years old.", name, age);
 }
-
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-// Take a look at the Data Types -> The Tuple Type section of the book:
-// https://doc.rust-lang.org/book/ch03-02-data-types.html#the-tuple-type
-// Particularly the part about destructuring (second to last example in the section).
-// You'll need to make a pattern to bind `name` and `age` to the appropriate parts
-// of the tuple. You can do it!!

exercises/primitive_types/primitive_types6.rs

@@ -1,45 +1,16 @@
 // primitive_types6.rs
 // Use a tuple index to access the second element of `numbers`.
-// You can put this right into the `println!` where the ??? is.
-// Scroll down for hints!
+// You can put the expression for the second element where ??? is so that the test passes.
+// Execute `rustlings hint primitive_types6` for hints!
 
-fn main() {
+// I AM NOT DONE
+
+#[test]
+fn indexing_tuple() {
     let numbers = (1, 2, 3);
-    println!("The second number is {}", ???);
+    // Replace below ??? with the tuple indexing syntax.
+    let second = ???;
+
+    assert_eq!(2, second,
+        "This is not the 2nd number in the tuple!")
 }
-
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-// While you could use a destructuring `let` for the tuple here, try
-// indexing into it instead, as explained in the last example of the
-// Data Types -> The Tuple Type section of the book:
-// https://doc.rust-lang.org/book/ch03-02-data-types.html#the-tuple-type
-// Now you have another tool in your toolbox!

exercises/quiz1.rs

@@ -1,12 +1,14 @@
-// test1.rs
-// This is a test for the following sections:
+// quiz1.rs
+// This is a quiz for the following sections:
 // - Variables
 // - Functions
 
-// Mary is buying apples. One apple usually costs 2 dollars, but if you buy
+// Mary is buying apples. One apple usually costs 2 Rustbucks, but if you buy
 // more than 40 at once, each apple only costs 1! Write a function that calculates
 // the price of an order of apples given the order amount. No hints this time!
 
+// I AM NOT DONE
+
 // Put your function here!
 // fn ..... {
 

exercises/quiz2.rs

@@ -0,0 +1,30 @@
+// quiz2.rs
+// This is a quiz for the following sections:
+// - Strings
+
+// Ok, here are a bunch of values-- some are `String`s, some are `&str`s. Your
+// task is to call one of these two functions on each value depending on what
+// you think each value is. That is, add either `string_slice` or `string`
+// before the parentheses on each line. If you're right, it will compile!
+
+// I AM NOT DONE
+
+fn string_slice(arg: &str) {
+    println!("{}", arg);
+}
+fn string(arg: String) {
+    println!("{}", arg);
+}
+
+fn main() {
+    ???("blue");
+    ???("red".to_string());
+    ???(String::from("hi"));
+    ???("rust is fun!".to_owned());
+    ???("nice weather".into());
+    ???(format!("Interpolation {}", "Station"));
+    ???(&String::from("abc")[0..1]);
+    ???("  hello there ".trim());
+    ???("Happy Monday!".to_string().replace("Mon", "Tues"));
+    ???("mY sHiFt KeY iS sTiCkY".to_lowercase());
+}

exercises/quiz3.rs

@@ -1,12 +1,14 @@
-// test3.rs
-// This is a test for the following sections:
+// quiz3.rs
+// This is a quiz for the following sections:
 // - Tests
 
-// This test isn't testing our function -- make it do that in such a way that
+// This quiz isn't testing our function -- make it do that in such a way that
 // the test passes. Then write a second test that tests that we get the result
 // we expect to get when we call `times_two` with a negative number.
 // No hints, you can do this :)
 
+// I AM NOT DONE
+
 pub fn times_two(num: i32) -> i32 {
     num * 2
 }

exercises/quiz4.rs

@@ -0,0 +1,23 @@
+// quiz4.rs
+// This quiz covers the sections:
+// - Modules
+// - Macros
+
+// Write a macro that passes the quiz! No hints this time, you can do it!
+
+// I AM NOT DONE
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+
+    #[test]
+    fn test_my_macro_world() {
+        assert_eq!(my_macro!("world!"), "Hello world!");
+    }
+
+    #[test]
+    fn test_my_macro_goodbye() {
+        assert_eq!(my_macro!("goodbye!"), "Hello goodbye!");
+    }
+}

exercises/standard_library_types/README.md

@@ -1,5 +1,5 @@
+For the Box exercise check out the chapter [Using Box to Point to Data on the Heap](https://doc.rust-lang.org/book/ch15-01-box.html).
+
 For the Arc exercise check out the chapter [Shared-State Concurrency](https://doc.rust-lang.org/book/ch16-03-shared-state.html) of the Rust Book.
 
 For the Iterator exercise check out the chapters [Iterator](https://doc.rust-lang.org/book/ch13-02-iterators.html) of the Rust Book and the [Iterator documentation](https://doc.rust-lang.org/stable/std/iter/).
-Do not adjust your monitors-- iterators 1 and 2 are indeed missing. Iterator 3 is a bit challenging so we're leaving space for some exercises to lead up to it!
-

exercises/standard_library_types/arc1.rs

@@ -1,9 +1,12 @@
 // arc1.rs
 // Make this code compile by filling in a value for `shared_numbers` where the
-// TODO comment is and creating an initial binding for `child_numbers`
+// TODO comment is and create an initial binding for `child_numbers`
 // somewhere. Try not to create any copies of the `numbers` Vec!
-// Scroll down for hints :)
+// Execute `rustlings hint arc1` for hints :)
 
+// I AM NOT DONE
+
+#![forbid(unused_imports)] // Do not change this, (or the next) line.
 use std::sync::Arc;
 use std::thread;
 
@@ -18,7 +21,7 @@ fn main() {
             let mut sum = 0;
             while i < child_numbers.len() {
                 sum += child_numbers[i];
-                i += 5;
+                i += 8;
             }
             println!("Sum of offset {} is {}", offset, sum);
         }));
@@ -27,29 +30,3 @@ fn main() {
         handle.join().unwrap();
     }
 }
-
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-
-// Make `shared_numbers` be an `Arc` from the numbers vector. Then, in order
-// to avoid creating a copy of `numbers`, you'll need to create `child_numbers`
-// inside the loop but still in the main thread.
-
-// `child_numbers` should be a clone of the Arc of the numbers instead of a
-// thread-local copy of the numbers.

exercises/standard_library_types/box1.rs

@@ -0,0 +1,56 @@
+// box1.rs
+//
+// At compile time, Rust needs to know how much space a type takes up. This becomes problematic
+// for recursive types, where a value can have as part of itself another value of the same type.
+// To get around the issue, we can use a `Box` - a smart pointer used to store data on the heap,
+// which also allows us to wrap a recursive type.
+//
+// The recursive type we're implementing in this exercise is the `cons list` - a data structure
+// frequently found in functional programming languages. Each item in a cons list contains two
+// elements: the value of the current item and the next item. The last item is a value called `Nil`.
+//
+// Step 1: use a `Box` in the enum definition to make the code compile
+// Step 2: create both empty and non-empty cons lists by replacing `unimplemented!()`
+//
+// Note: the tests should not be changed
+//
+// Execute `rustlings hint box1` for hints :)
+
+// I AM NOT DONE
+
+#[derive(PartialEq, Debug)]
+pub enum List {
+    Cons(i32, List),
+    Nil,
+}
+
+fn main() {
+    println!("This is an empty cons list: {:?}", create_empty_list());
+    println!(
+        "This is a non-empty cons list: {:?}",
+        create_non_empty_list()
+    );
+}
+
+pub fn create_empty_list() -> List {
+    unimplemented!()
+}
+
+pub fn create_non_empty_list() -> List {
+    unimplemented!()
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+
+    #[test]
+    fn test_create_empty_list() {
+        assert_eq!(List::Nil, create_empty_list())
+    }
+
+    #[test]
+    fn test_create_non_empty_list() {
+        assert_ne!(create_empty_list(), create_non_empty_list())
+    }
+}

exercises/standard_library_types/iterators1.rs

@@ -0,0 +1,24 @@
+// iterators1.rs
+// 
+//  Make me compile by filling in the `???`s
+//
+// When performing operations on elements within a collection, iterators are essential.
+// This module helps you get familiar with the structure of using an iterator and 
+// how to go through elements within an iterable collection.
+// 
+// Execute `rustlings hint iterators1` for hints :D
+
+// I AM NOT DONE
+
+fn main () {
+    let my_fav_fruits = vec!["banana", "custard apple", "avocado", "peach", "raspberry"];
+
+    let mut my_iterable_fav_fruits = ???;   // TODO: Step 1
+
+    assert_eq!(my_iterable_fav_fruits.next(), Some(&"banana"));
+    assert_eq!(my_iterable_fav_fruits.next(), ???);     // TODO: Step 2
+    assert_eq!(my_iterable_fav_fruits.next(), Some(&"avocado"));
+    assert_eq!(my_iterable_fav_fruits.next(), ???);     // TODO: Step 2.1
+    assert_eq!(my_iterable_fav_fruits.next(), Some(&"raspberry"));
+    assert_eq!(my_iterable_fav_fruits.next(), ???);     // TODO: Step 3
+}

exercises/standard_library_types/iterators2.rs

@@ -1,9 +1,13 @@
 // iterators2.rs
-// In this module, you'll learn some of unique advantages that iterators can offer
-// Step 1. Complete the `capitalize_first` function to pass the first two cases
-// Step 2. Apply the `capitalize_first` function to a vector of strings, ensuring that it returns a vector of strings as well
-// Step 3. Apply the `capitalize_first` function again to a list, but try and ensure it returns a single string
-// As always, there are hints below!
+// In this module, you'll learn some of the unique advantages that iterators can offer.
+// Step 1. Complete the `capitalize_first` function to pass the first two cases.
+// Step 2. Apply the `capitalize_first` function to a vector of strings.
+//         Ensure that it returns a vector of strings as well.
+// Step 3. Apply the `capitalize_first` function again to a list.
+//         Try to ensure it returns a single string.
+// As always, there are hints if you execute `rustlings hint iterators2`!
+
+// I AM NOT DONE
 
 pub fn capitalize_first(input: &str) -> String {
     let mut c = input.chars();
@@ -44,102 +48,3 @@ mod tests {
         assert_eq!(capitalized_words, "Hello World");
     }
 }
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-// Step 1
-// You need to call something on `first` before it can be collected
-// Currently its type is `char`. Have a look at the methods that are available on that type:
-// https://doc.rust-lang.org/std/primitive.char.html
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-// Step 2
-// First you'll need to turn the Vec into an iterator
-// Then you'll need to apply your function unto each item in the vector
-// P.s. Don't forget to collect() at the end!
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-// Step 3.
-// This is very similar to the previous test. The only real change is that you will need to
-// alter the type that collect is coerced into. For a bonus you could try doing this with a
-// turbofish

exercises/standard_library_types/iterators3.rs

@@ -4,10 +4,11 @@
 // 1. Complete the divide function to get the first four tests to pass
 // 2. Uncomment the last two tests and get them to pass by filling in
 //    values for `x` using `division_results`.
-// Scroll down for a minor hint for part 2, and scroll down further for
-// a major hint.
+// Execute `rustlings hint iterators3` to get some hints!
 // Have fun :-)
 
+// I AM NOT DONE
+
 #[derive(Debug, PartialEq, Eq)]
 pub enum DivisionError {
     NotDivisible(NotDivisibleError),
@@ -75,72 +76,3 @@ mod tests {
     }
     */
 }
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-// Minor hint: In each of the two cases in the match in main, you can create x with either
-// a 'turbofish' or by hinting the type of x to the compiler. You may try both.
-
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-// Major hint: Have a look at the Iter trait and at the explanation of its collect function.
-// Especially the part about Result is interesting.

exercises/standard_library_types/iterators4.rs

@@ -1,15 +1,17 @@
 // iterators4.rs
 
+// I AM NOT DONE
+
 pub fn factorial(num: u64) -> u64 {
-    // Complete this function to return factorial of num
+    // Complete this function to return the factorial of num
     // Do not use:
     // - return
-    // For extra fun don't use:
+    // Try not to use:
     // - imperative style loops (for, while)
     // - additional variables
-    // For the most fun don't use:
+    // For an extra challenge, don't use:
     // - recursion
-    // Scroll down for hints.
+    // Execute `rustlings hint iterators4` for hints.
 }
 
 #[cfg(test)]
@@ -30,32 +32,3 @@ mod tests {
         assert_eq!(24, factorial(4));
     }
 }
-
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-// In an imperative language you might write a for loop to iterate through
-// multiply the values into a mutable variable. Or you might write code more
-// functionally with recursion and a match clause. But you can also use ranges
-// and iterators to solve this in rust.

exercises/strings/strings1.rs

@@ -1,5 +1,8 @@
 // strings1.rs
-// Make me compile without changing the function signature! Scroll down for hints :)
+// Make me compile without changing the function signature!
+// Execute `rustlings hint strings1` for hints ;)
+
+// I AM NOT DONE
 
 fn main() {
     let answer = current_favorite_color();
@@ -9,38 +12,3 @@ fn main() {
 fn current_favorite_color() -> String {
     "blue"
 }
-
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-// The `current_favorite_color` function is currently returning a string slice with the `'static`
-// lifetime. We know this because the data of the string lives in our code itself -- it doesn't
-// come from a file or user input or another program -- so it will live as long as our program
-// lives. But it is still a string slice. There's one way to create a `String` by converting a
-// string slice covered in the Strings chapter of the book, and another way that uses the `From`
-// trait.

exercises/strings/strings2.rs

@@ -1,5 +1,8 @@
 // strings2.rs
-// Make me compile without changing the function signature! Scroll down for hints :)
+// Make me compile without changing the function signature!
+// Execute `rustlings hint strings2` for hints :)
+
+// I AM NOT DONE
 
 fn main() {
     let word = String::from("green"); // Try not changing this line :)
@@ -13,32 +16,3 @@ fn main() {
 fn is_a_color_word(attempt: &str) -> bool {
     attempt == "green" || attempt == "blue" || attempt == "red"
 }
-
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-// Yes, it would be really easy to fix this by just changing the value bound to `word` to be a
-// string slice instead of a `String`, wouldn't it?? There is a way to add one character to line
-// 6, though, that will coerce the `String` into a string slice.

exercises/structs/structs1.rs

@@ -1,6 +1,8 @@
 // structs1.rs
 // Address all the TODOs to make the tests pass!
 
+// I AM NOT DONE
+
 struct ColorClassicStruct {
     // TODO: Something goes here
 }

exercises/structs/structs2.rs

@@ -1,6 +1,7 @@
 // structs2.rs
 // Address all the TODOs to make the tests pass!
-// No hints, just do it!
+
+// I AM NOT DONE
 
 #[derive(Debug)]
 struct Order {

exercises/structs/structs3.rs

@@ -0,0 +1,71 @@
+// structs3.rs
+// Structs contain more than simply some data, they can also have logic, in this
+// exercise we have defined the Package struct and we want to test some logic attached to it,
+// make the code compile and the tests pass! If you have issues execute `rustlings hint structs3`
+
+// I AM NOT DONE
+
+#[derive(Debug)]
+struct Package {
+    sender_country: String,
+    recipient_country: String,
+    weight_in_grams: i32,
+}
+
+impl Package {
+    fn new(sender_country: String, recipient_country: String, weight_in_grams: i32) -> Package {
+        if weight_in_grams <= 0 {
+            // Something goes here...
+        } else {
+            return Package {
+                sender_country,
+                recipient_country,
+                weight_in_grams,
+            };
+        }
+    }
+
+    fn is_international(&self) -> ??? {
+        // Something goes here...
+    }
+
+    fn get_fees(&self, cents_per_gram: i32) -> ??? {
+        // Something goes here... 
+    }
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+
+    #[test]
+    #[should_panic]
+    fn fail_creating_weightless_package() {
+        let sender_country = String::from("Spain");
+        let recipient_country = String::from("Austria");
+
+        Package::new(sender_country, recipient_country, -2210);
+    }
+
+    #[test]
+    fn create_international_package() {
+        let sender_country = String::from("Spain");
+        let recipient_country = String::from("Russia");
+
+        let package = Package::new(sender_country, recipient_country, 1200);
+
+        assert!(package.is_international());
+    }
+
+    #[test]
+    fn calculate_transport_fees() {
+        let sender_country = String::from("Spain");
+        let recipient_country = String::from("Spain");
+
+        let cents_per_gram = ???;
+
+        let package = Package::new(sender_country, recipient_country, 1500);
+
+        assert_eq!(package.get_fees(cents_per_gram), 4500);
+    }
+}

exercises/test2.rs

@@ -1,28 +0,0 @@
-// test2.rs
-// This is a test for the following sections:
-// - Strings
-
-// Ok, here are a bunch of values-- some are `Strings`, some are `&strs`. Your
-// task is to call one of these two functions on each value depending on what
-// you think each value is. That is, add either `string_slice` or `string`
-// before the parentheses on each line. If you're right, it will compile!
-
-fn string_slice(arg: &str) {
-    println!("{}", arg);
-}
-fn string(arg: String) {
-    println!("{}", arg);
-}
-
-fn main() {
-    ("blue");
-    ("red".to_string());
-    (String::from("hi"));
-    ("rust is fun!".to_owned());
-    ("nice weather".into());
-    (format!("Interpolation {}", "Station"));
-    (&String::from("abc")[0..1]);
-    ("  hello there ".trim());
-    ("Happy Monday!".to_string().replace("Mon", "Tues"));
-    ("mY sHiFt KeY iS sTiCkY".to_lowercase());
-}

exercises/test4.rs

@@ -1,12 +0,0 @@
-// test4.rs
-// This test covers the sections:
-// - Modules
-// - Macros
-
-// Write a macro that passes the test! No hints this time, you can do it!
-
-fn main() {
-    if my_macro!("world!") != "Hello world!" {
-        panic!("Oh no! Wrong output!");
-    }
-}

exercises/tests/tests1.rs

@@ -1,10 +1,12 @@
 // tests1.rs
 // Tests are important to ensure that your code does what you think it should do.
 // Tests can be run on this file with the following command:
-// rustlings run --test exercises/tests/tests1.rs
+// rustlings run tests1
 
 // This test has a problem with it -- make the test compile! Make the test
-// pass! Make the test fail! Scroll down for hints :)
+// pass! Make the test fail! Execute `rustlings hint tests1` for hints :)
+
+// I AM NOT DONE
 
 #[cfg(test)]
 mod tests {
@@ -13,37 +15,3 @@ mod tests {
         assert!();
     }
 }
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-// You don't even need to write any code to test -- you can just test values and run that, even
-// though you wouldn't do that in real life :) `assert!` is a macro that needs an argument.
-// Depending on the value of the argument, `assert!` will do nothing (in which case the test will
-// pass) or `assert!` will panic (in which case the test will fail). So try giving different values
-// to `assert!` and see which ones compile, which ones pass, and which ones fail :)

exercises/tests/tests2.rs

@@ -1,6 +1,8 @@
 // tests2.rs
 // This test has a problem with it -- make the test compile! Make the test
-// pass! Make the test fail! Scroll down for hints :)
+// pass! Make the test fail! Execute `rustlings hint tests2` for hints :)
+
+// I AM NOT DONE
 
 #[cfg(test)]
 mod tests {
@@ -9,36 +11,3 @@ mod tests {
         assert_eq!();
     }
 }
-
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-// Like the previous exercise, you don't need to write any code to get this test to compile and
-// run. `assert_eq!` is a macro that takes two arguments and compares them. Try giving it two
-// values that are equal! Try giving it two arguments that are different! Try giving it two values
-// that are of different types! Try switching which argument comes first and which comes second!

exercises/tests/tests3.rs

@@ -1,7 +1,10 @@
 // tests3.rs
 // This test isn't testing our function -- make it do that in such a way that
 // the test passes. Then write a second test that tests whether we get the result
-// we expect to get when we call `is_even(5)`. Scroll down for hints!
+// we expect to get when we call `is_even(5)`.
+// Execute `rustlings hint tests3` for hints :)
+
+// I AM NOT DONE
 
 pub fn is_even(num: i32) -> bool {
     num % 2 == 0
@@ -15,29 +18,9 @@ mod tests {
     fn is_true_when_even() {
         assert!();
     }
+
+    #[test]
+    fn is_false_when_odd() {
+        assert!();
+    }
 }
-
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-// You can call a function right where you're passing arguments to `assert!` -- so you could do
-// something like `assert!(having_fun())`. If you want to check that you indeed get false, you
-// can negate the result of what you're doing using `!`, like `assert!(!having_fun())`.

exercises/threads/threads1.rs

@@ -1,10 +1,12 @@
 // threads1.rs
-// Make this compile! Scroll down for hints :) The idea is the thread
-// spawned on line 19 is completing jobs while the main thread is
+// Make this compile! Execute `rustlings hint threads1` for hints :)
+// The idea is the thread spawned on line 21 is completing jobs while the main thread is
 // monitoring progress until 10 jobs are completed. If you see 6 lines
-// of "waiting..." and the program ends without timing out the playground,
+// of "waiting..." and the program ends without timing out when running,
 // you've got it :)
 
+// I AM NOT DONE
+
 use std::sync::Arc;
 use std::thread;
 use std::time::Duration;
@@ -27,69 +29,3 @@ fn main() {
         thread::sleep(Duration::from_millis(500));
     }
 }
-
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-
-// `Arc` is an Atomic Reference Counted pointer that allows safe, shared access
-// to **immutable** data. But we want to *change* the number of `jobs_completed`
-// so we'll need to also use another type that will only allow one thread to
-// mutate the data at a time. Take a look at this section of the book:
-// https://doc.rust-lang.org/book/ch16-03-shared-state.html#atomic-reference-counting-with-arct
-// and keep scrolling if you'd like more hints :)
-
-
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-// Do you now have an `Arc` `Mutex` `JobStatus` at the beginning of main? Like:
-// `let status = Arc::new(Mutex::new(JobStatus { jobs_completed: 0 }));`
-// Similar to the code in the example in the book that happens after the text
-// that says "We can use Arc<T> to fix this.". If not, give that a try! If you
-// do and would like more hints, keep scrolling!!
-
-
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-// Make sure neither of your threads are holding onto the lock of the mutex
-// while they are sleeping, since this will prevent the other thread from
-// being allowed to get the lock. Locks are automatically released when
-// they go out of scope.
-
-// Ok, so, real talk, this was actually tricky for *me* to do too. And
-// I could see a lot of different problems you might run into, so at this
-// point I'm not sure which one you've hit :) Please see a few possible
-// answers on https://github.com/carols10cents/rustlings/issues/3 --
-// mine is a little more complicated because I decided I wanted to see
-// the number of jobs currently done when I was checking the status.
-
-// Please open an issue if you're still running into a problem that
-// these hints are not helping you with, or if you've looked at the sample
-// answers and don't understand why they work and yours doesn't.
-
-// If you've learned from the sample solutions, I encourage you to come
-// back to this exercise and try it again in a few days to reinforce
-// what you've learned :)

exercises/traits/README.md

@@ -0,0 +1,20 @@
+### Traits
+
+A trait is a collection of methods.
+
+Data types can implement traits. To do so, the methods making up the trait are defined for the data type. For example, the `String` data type implements the `From<&str>` trait. This allows a user to write `String::from("hello")`.
+
+In this way, traits are somewhat similar to Java interfaces and C++ abstract classes.
+
+Some additional common Rust traits include:
+
++ `Clone` (the `clone` method),
++ `Display` (which allows formatted display via `{}`), and
++ `Debug` (which allows formatted display via `{:?}`).
+
+Because traits indicate shared behavior between data types, they are useful when writing generics.
+
+
+#### Book Sections
+
+- [Traits](https://doc.rust-lang.org/book/ch10-02-traits.html)

exercises/traits/traits1.rs

@@ -0,0 +1,43 @@
+// traits1.rs
+// Time to implement some traits!
+//
+// Your task is to implement the trait
+// `AppendBar' for the type `String'.
+//
+// The trait AppendBar has only one function,
+// which appends "Bar" to any object
+// implementing this trait.
+
+// I AM NOT DONE
+
+trait AppendBar {
+    fn append_bar(self) -> Self;
+}
+
+impl AppendBar for String {
+    //Add your code here
+}
+
+fn main() {
+    let s = String::from("Foo");
+    let s = s.append_bar();
+    println!("s: {}", s);
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+
+    #[test]
+    fn is_FooBar() {
+        assert_eq!(String::from("Foo").append_bar(), String::from("FooBar"));
+    }
+
+    #[test]
+    fn is_BarBar() {
+        assert_eq!(
+            String::from("").append_bar().append_bar(),
+            String::from("BarBar")
+        );
+    }
+}

exercises/traits/traits2.rs

@@ -0,0 +1,31 @@
+// traits2.rs
+//
+// Your task is to implement the trait
+// `AppendBar' for a vector of strings.
+//
+// To implement this trait, consider for
+// a moment what it means to 'append "Bar"'
+// to a vector of strings.
+//
+// No boiler plate code this time,
+// you can do this!
+
+// I AM NOT DONE
+
+trait AppendBar {
+    fn append_bar(self) -> Self;
+}
+
+//TODO: Add your code here
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+
+    #[test]
+    fn is_vec_pop_eq_bar() {
+        let mut foo = vec![String::from("Foo")].append_bar();
+        assert_eq!(foo.pop().unwrap(), String::from("Bar"));
+        assert_eq!(foo.pop().unwrap(), String::from("Foo"));
+    }
+}

exercises/variables/variables1.rs

@@ -1,42 +1,14 @@
 // variables1.rs
-// Make me compile! Scroll down for hints :)
+// Make me compile! Execute the command `rustlings hint variables1` if you want a hint :)
+
+// About this `I AM NOT DONE` thing:
+// We sometimes encourage you to keep trying things on a given exercise,
+// even after you already figured it out. If you got everything working and
+// feel ready for the next exercise, remove the `I AM NOT DONE` comment below.
+
+// I AM NOT DONE
 
 fn main() {
     x = 5;
     println!("x has the value {}", x);
 }
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-// Hint: The declaration on line 5 is missing a keyword that is needed in Rust
-// to create a new variable binding.

exercises/variables/variables2.rs

@@ -1,5 +1,7 @@
 // variables2.rs
-// Make me compile! Scroll down for hints :)
+// Make me compile! Execute the command `rustlings hint variables2` if you want a hint :)
+
+// I AM NOT DONE
 
 fn main() {
     let x;
@@ -9,39 +11,3 @@ fn main() {
         println!("Not ten!");
     }
 }
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-// The compiler message is saying that Rust cannot infer the type that the
-// variable binding `x` has with what is given here.
-// What happens if you annotate line 5 with a type annotation?
-// What if you give x a value?
-// What if you do both?
-// What type should x be, anyway?
-// What if x is the same type as 10? What if it's a different type?

exercises/variables/variables3.rs

@@ -1,43 +1,11 @@
 // variables3.rs
-// Make me compile! Scroll down for hints :)
+// Make me compile! Execute the command `rustlings hint variables3` if you want a hint :)
+
+// I AM NOT DONE
 
 fn main() {
     let x = 3;
     println!("Number {}", x);
-    x = 5;
+    x = 5; // don't change this line
     println!("Number {}", x);
 }
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-// In Rust, variable bindings are immutable by default. But here we're trying
-// to reassign a different value to x! There's a keyword we can use to make
-// a variable binding mutable instead.

exercises/variables/variables4.rs

@@ -1,45 +1,9 @@
 // variables4.rs
-// Make me compile! Scroll down for hints :)
+// Make me compile! Execute the command `rustlings hint variables4` if you want a hint :)
+
+// I AM NOT DONE
 
 fn main() {
     let x: i32;
     println!("Number {}", x);
 }
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-// Oops! In this exercise, we have a variable binding that we've created on
-// line 5, and we're trying to use it on line 6, but we haven't given it a
-// value. We can't print out something that isn't there; try giving x a value!
-// This is an error that can cause bugs that's very easy to make in any
-// programming language -- thankfully the Rust compiler has caught this for us!

exercises/variables/variables5.rs

@@ -0,0 +1,11 @@
+// variables5.rs
+// Make me compile! Execute the command `rustlings hint variables5` if you want a hint :)
+
+// I AM NOT DONE
+
+fn main() {
+    let number = "T-H-R-E-E";
+    println!("Spell a Number : {}", number);
+    number = 3;
+    println!("Number plus two is : {}", number + 2);
+}

exercises/variables/variables6.rs

@@ -0,0 +1,9 @@
+// variables6.rs
+// Make me compile! Execute the command `rustlings hint variables6` if you want a hint :)
+
+// I AM NOT DONE
+
+const NUMBER = 3;
+fn main() {
+    println!("Number {}", NUMBER);
+}